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This study aimed to investigate the effects of acid or alkali modification of isolated cassava starch (ICS) on its physicochemical properties. Acetic acid concentrations of 5%, 10%, and 20% v/v (0.87, 1.73, and 3.46 M, respectively) and calcium hydroxide concentrations of 0.15%, 0.20%, and 0.30% w/w (0.02, 0.025, and 0.04 M, respectively) were tested independently and compared with untreated isolated starch. The scanning electron microscope (SEM) shows starches with polyhedral and semispherical shapes; these modifications do not change the surface of the starch granules. Nanocrystals with orthorhombic crystal structure were extracted from ICS. Transmission electron microscopy (TEM) shows crystallites with a size (two‐dimensional) of 20 ± 5 nm in length and 10 ± 2 nm in width and reveals that this starch contains nanocrystals with orthorhombic crystal structure. The X‐ray patterns show that these nanocrystals are unaffected by acidic or alkaline treatments. The Ca+2 and CH3COO− ions do not interact with these nanocrystals. The alkaline treatment only affects the gelatinization temperature at a Ca(OH)2 concentration of 0.30%. Low concentrations of acidic and alkaline treatments affect the ability of cassava starch to absorb water and reduce the peak and final viscosity. The infrared spectra show that the modifications lead to C–H and C═C bond formations. ICS‐B 0.30 can modify the amorphous regions of the starch, and the acid treatment leads to acetylation, which was confirmed by the presence of an IR band at 1740 cm−1. [ABSTRACT FROM AUTHOR]

Dentin tissue can act as a reservoir for bioactive molecules that create signals for cellular proliferation and differentiation to initiate tissue regeneration. Therefore, the aim of this study is to compare the cell viability, inflammatory response, and antimicrobial activity of bovine dentin grain-added calcium-hydroxide (CH-BDG) with different pulp-capping materials.ProRoot MTA, Biodentine, Dycal, TheraCal-LC, and an experimental material, CH-BDG, were examined. Cell viability was determined via the WST-1 assay. The inflammatory response was analysed by the monocyte chemoattractant protein-1 (MCP-1/CCL2) and macrophage inflammatory protein-1α (MIP-1α/CCL3) levels. The antimicrobial activity was evaluated by agar-diffusion.The cell viability of CH-BDG was analogous with Biodentine and control at 24 h. The cell viability of CH-BDG decreased at 48 h, but the rate was higher than ProRoot MTA and Dycal (p<0.05). For MCP-1 and MIP-1α values, there was no significant difference between the control and CH-BDG. The MCP-1 level of CH-BDG was lower compared to other pulp-capping materials (p<0.05). The MIP-1α level of CH-BDG was lower compared to ProRoot MTA, Biodentine, and TheraCal-LC (p<0.05). No inhibition zone was detected against oral microorganisms for CH-BDG.The experimentally developed CH-BDG showed competing properties and additional advantages compared to the existing pulp-capping materials. [ABSTRACT FROM AUTHOR]

With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation. [ABSTRACT FROM AUTHOR]

The efficiency of stabilization/solidification (S/S) treated heavy metal contaminated soils may be deteriorated by the changeable external environment. Thus, the toxicity characteristics leaching procedure (TCLP) and pH-dependent leaching test were carried out to evaluate the toxicity of zinc-contaminated soil treated by cement blended with soda residue with consideration of freezing–thawing (F-T) cycles. Results showed that F-T cycles had little impact on the toxicity of Zn-contaminated soils treated with cement-soda residue, and the leached Zn2+ concentration didn't exceed the regulatory limit defined by the standards. Dissolution/precipitation of zinc hydroxides was suggested to be the controlling mechanism for Zn2+ leachability. Besides, Zn2+ immobilized by chemical incorporation and encapsulation by calcium silicate hydrates (CSHs) and calcium aluminate hydrates (CAHs) still remained stable in an acidic condition. Results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) verified that F-T cycles impose little impact on the chemical properties of the specimens, but only alter the micro- and macrostructure characteristics. [ABSTRACT FROM AUTHOR]

Aim: Calcium hydroxide (CH) has been considered as a direct pulp capping materials (DPC) for the last decades despite having some limitations. Phosphorylate pullulan (PPL) incorporated with CH (CHPPL) is a novel biomaterial that was introduced as a promising DPC material. Thus, the aim of the study was to evaluate the inflammatory response and mineralized tissue formation (MTF) ability of PPL‐based CH formulations on rat molars after DPC. Methodology: This study consisted of six groups: CH with 1% PPL (CHPPL‐1); 3% PPL (CHPPL‐3); 5% PPL (CHPPL‐5); Dycal and NEX MTA Cement (N‐MTA) as the positive control, and no capping materials (NC). One hundred twenty maxillary first molar cavities were prepared on Wistar rats. After capping, all the cavities were restored with 4‐META/MMA‐TBB resin and pulpal responses were evaluated at days 1, 7, and 28. Kruskal–Wallis followed by Mann–Whitney U‐test was performed with a significance level of 0.05. Immunohistochemical expression of IL‐6, Nestin, and DMP‐1 was observed. Results: At day 1, CHPPL‐1, N‐MTA, and Dycal exhibited no to mild inflammation, whilst CHPPL‐3, CHPPL‐5, and NC showed mild to moderate inflammation, and the results were significantly different (p <.05). At day 7, mild to moderate inflammation was observed in CHPPL‐1, N‐MTA, and Dycal, whereas CHPPL‐3, CHPPL‐5, and NC exhibited moderate to severe inflammation. Significant differences were observed between CHPPL‐1 and N‐MTA with NC (p <.05), CHPPL‐1 and CHPPL‐3 with CHPPL‐5 and Dycal (p <.05), and CHPPL‐3 with N‐MTA (p <.05). A thin layer of mineralized tissue formation (MTF) was observed in all groups. At day 28, CHPPL‐1, Dycal, and N‐MTA showed no to mild inflammation, whilst CHPPL‐3, CHPPL‐5, and NC exhibited mild to severe inflammation, and statistically significant difference was detected (p <.05). CHPPL‐1, Dycal, and N‐MTA exhibited continuous MTF, whilst CHPPL‐3, CHPPL‐5, and NC had thicker and interrupted MTF. Significant differences were observed between CHPPL‐1, CHPPL‐3, and N‐MTA with NC group (p <.05). Variable expressions of IL‐6, Nestin, and DMP‐1 indicated differences in the materials' impact on odontoblast‐like cell formation and tissue mineralization. Conclusions: These findings suggest that CHPPL‐1 has the potential to minimize pulpal inflammation and promote MTF and had similar efficacy as MTA cement. [ABSTRACT FROM AUTHOR]

The yield of green energy from solid-state anaerobic co-digestion (SSAD) has recently been enhanced by incorporating innovative pretreatment methods and nanoparticles. However, the environmental consequences of employing new processes have not been fully examined. In this study, the environmental impacts of three high-methane-yielding scenarios including SSAD of corn stover blended with dairy manure (DM) denoted as (SYM1), calcium hydroxide-pretreated corn stover (CpCS) blended with DM (SYM2), and the CpCS blended with DM and nanoparticles (SYM3) were assessed and compared the baselines of solid-state and semi-solid-state anaerobic digestion using a life cycle assessment (LCA) approach. The approach investigated the best management practices that would result in high methane yield and low environmental impact. Results of the life cycle assessment indicate the inclusion of calcium hydroxide and nanoparticle has minimal negative environmental impact. There was an environmental gain in GWP when corn stover was co-digestion with DM (SYM1) relative to DM mono-digestions (baselines) and the carbon footprint of SYM1 was less by more than 85% compared to SYM2 and SYM3. However, the large volume of untreated corn stover harnessed for SYM1 scenario resulted in over 75% fossil fuel depletion compared to the other scenarios. The surplus methane from the SYM3 (at least twofold of other scenarios and baselines) in conjunction with being the least with the environmental implication makes the scenario the most attractive option for on-farm practice capable of harnessing the growing organic waste volume. These outcomes can guide trade-off between pretreatment and nanoparticle application to reduce solid-state anaerobic digestion's negative environmental impact. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to assess the efficacy of different activation techniques in removing calcium hydroxide (Ultracal XS), Ledermix, and Bio-C Temp from simulated internal root resorption (IRR) cavities. Materials and methods: 108 single-rooted maxillary incisors were prepared using Reciproc R50 files. Simulated IRR cavities, 2 mm in diameter and located 8 mm from the apex, were created. Ultracal XS, Ledermix, and Bio-C Temp were applied to the samples, grouped by irrigation activation techniques: Standard Needle Irrigation (SNI), EDDY, Passive Ultrasonic Irrigation (PUI), and XP-endo Finisher (XPF). Medicament removal efficacy was evaluated using a standardized scoring system. Statistical analysis was performed using the Kruskal-Wallis test. Results: XPF and PUI were more effective than SNI in medicament removal across the groups, with no significant difference. EDDY showed no significant difference than other groups. Ledermix was more effectively removed in all activation groups compared to Bio-C Temp. The XPF was superior in removing Ultracal XS compared to Bio-C Temp. However, none of the groups achieved complete medicament removal. Conclusions: XPF and PUI techniques enhance medicament removal efficacy. Bio-C Temp was more difficult to remove from the IRR cavities than other medicaments. Clinical relevance: Bio-C Temp could be removed from the canals less effectively compared to calcium hydroxide and Ledermix. Among the tested irrigation activation methods, XPF and PUI were found to be more effective at removing the tested medicaments. [ABSTRACT FROM AUTHOR]

Electric reduction furnaces cannot be fed fines in the production of manganese ferroalloy as they hinder gas permeability. Thus, agglomeration techniques can be used to minimize the environmental and economic impacts of storing fines. Among these techniques, briquetting is advantageous because it allows for cold agglomeration of the particles and is flexible in terms of particle sizes. Therefore, this work aimed to develop self-reductor briquettes composed of ore manganese fines, dust ferromanganese, charcoal fines, and three different binders. The compaction pressure, curing time, and % binder were optimized to enhance briquette strength through a multivariate experimental design consisting of a screening study using a 23 full factorial design followed by response surface methodology with a spherical central composite design. The results were assessed by analysis of variance, and a regression model was established. The study found that briquettes elaborated with bentonite exhibited an optimized compressive strength of 4.02 MPa, achieved with a compaction pressure of 67.55 MPa and 12.71% bentonite. For briquettes elaborated with pregelatinized starch, a compressive strength of 7.04 MPa was obtained with a compaction pressure of 67.52 MPa, a curing time of 19.51 days, and 8.07% pregelatinized starch. For briquettes agglomerated using slaked lime and molasses, an optimized compaction pressure of 27.09 MPa and a curing time of 23.27 days resulted in a compressive strength of 1.63 MPa. These results suggest that briquettes containing bentonite and pregelatinized starch are feasible substitutes for lump ore in electric furnaces. [ABSTRACT FROM AUTHOR]

Calcium hydroxide was used as a swelling agent and grinding aid to grind together with cellulose raw materials to prepare microfibrillated cellulose (MFC). Carbon dioxide was introduced to obtain MFC coated with calcium carbonate (CMFC). The effect of calcium hydroxide dosage on the fibrillation process of cellulose materials and the characteristics of MFCs and CMFCs were studied. Results show that when the dosage of calcium hydroxide was 5 % (based on cellulose materials), calcium hydroxide could be completely dissolved in water and had a swelling effect on cellulose materials. When the dosage reached 10 %, undissolved calcium hydroxide particles could serve as grinding media to assist in the fibrillation of cellulose materials. When the dosage exceeded 50 %, the auxiliary grinding effect of calcium hydroxide was more obvious. After accelerated carbonation, the generated calcium carbonate nanoparticles were coated on the surface of MFC, which increased its viscosity and decreased water retention value. The presence of calcium carbonate also facilitated the concentration, redispersion, and drying of MFC. The pretreatment, mechanical fibrillation, and accelerated carbonation were carried out in the same equipment without the need for heating or washing. Therefore, this study provides a in situ and one step method for the preparation of MFC. [ABSTRACT FROM AUTHOR]

AbstractAs known, calcium hydroxide Ca(OH)2 is a basic material, that can be used in numerous applications. Recently, many trials have been performed to modify some properties of alkali-activated materials (AAMs) by introducing Ca(OH)2. In general, Ca(OH)2 can be introduced into AAMs in three forms: as a part of a precursor or as an additive, as a sole activator or combined with an auxiliary activator. The incorporation of Ca(OH)2 into different matrices may modify some properties or worsen others. This essentially depends on curing conditions, the ratio of Ca(OH)2, precursor type and fineness, activator type, activator concentration, and testing age. This review aimed to collect, summarize, and analyze the available studies regarding the effect of Ca(OH)2 on the properties of AAMs in its three forms. The review showed that most studies preferred using Ca(OH)2 as a part of precursor followed by using it as an activator combined with an auxiliary activator, with its use as the sole activator being least preferred. The review found that Ca(OH)2 incorporation in precursors reduced workability and setting time but increased carbonation resistance, with 5-30% Ca(OH)2 being the most effective activator. Auxiliary activator with Ca(OH)2 enhanced the strength. Additionally, some recommendations for the future were mentioned. [ABSTRACT FROM AUTHOR]

In 2020, Denmark buried approximately four million culled, farmed mink in mass graves treated with slaked lime due to widespread SARS-CoV-2 infections. After six months, environmental concerns prompted the exhumation of these cadavers. Our analysis encompassed visual inspections, soil pH measurements, and gas emission assessments of the grave environment. Additionally, we evaluated carcasses for decay status, cadaverine content, and the presence of various pathogens, including SARS-CoV-2 and mink coronavirus. Our findings revealed minimal microbial activity and limited carcass decomposition. Although viral RNA from SARS-CoV-2 and mink coronavirus, along with DNA from Aleutian mink disease virus, were detected, the absence of infectious SARS-CoV-2 in cell culture assays suggests slow natural degradation processes. This study provides critical insights for future considerations in managing mass burial scenarios during outbreaks of livestock-associated zoonotic pathogens. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of different irrigation activation methods on root canal sealer penetration in teeth with simulated internal root resorption (IRR) and calcium hydroxide (CH) applied using a confocal laser scanning microscope (CLSM). 60 incisors with a single root and a single canal were included in the study. IRR cavities were created in the middle third of the root canal, and CH was placed. The samples were randomly divided into 4 groups (n = 15) according to the irrigation activation method to be tested: standard needle irrigation (SNI), sonic activation (EDDY), photon-induced photoacoustic flow (PIPS), and shock wave enhanced emission photoacoustic flow (SWEEPS). After irrigation activation applications, the root canals were obturated. Sections of 1.0 ± 0.1 mm were taken from the apical, middle, and coronal regions of each sample. The penetration area (µm2) and maximum penetration depth (µm) of the root canal sealer were examined by CLSM and analyzed using ImageJ software. Statistical analysis was performed with a one-way ANOVA and post-hoc Tukey test at the P < 0.05 significance level. Among all irrigation activation methods tested, both the penetration area and maximum penetration depth of the root canal sealer were greater in the coronal region than in the apical region (p < 0.05). In the IRR region, there was no difference in terms of maximum penetration depth between PIPS and SWEEPS (p > 0.05), it was highest in SWEEPS (p < 0.05). PIPS and SWEEPS were better than other irrigation activation methods in the penetration of root canal sealer in the resorption areas of teeth with IRR. [ABSTRACT FROM AUTHOR]

Mineral Trioxide Aggregate (MTA) is the gold standard for vital pulp treatment (VPT), but its superiority over novel calcium silicate-based cements in permanent teeth lacks systematic evidence. This study aimed to compare the efficacy of these materials in VPT through a network meta-analysis. A systematic search was conducted in MEDLINE, EMBASE, Cochrane Library, and Web of Science until January 20, 2024. The inclusion criteria were randomized controlled trials involving VPT with biomaterials and reversible or irreversible pulpitis diagnoses in mature permanent teeth. The primary outcome was the odds ratio (OR) of failure rates with 95% confidence intervals. In the 21 eligible trials, failure rates were significantly higher with calcium-hydroxide than MTA at six (OR 2.26 [1.52-3.36]), 12 (OR 2.53 [1.76-3.62]), and 24 months (OR 2.46 [1.60-3.79]). Failure rates for Totalfill at six (OR 1.19 [0.55-2.58]) and 12 months (OR 1.43 [0.71-2.92]), and Biodentine at six (OR 1.09 [0.66-1.78]), 12 (OR 1.21 [0.74-1.96]), and 24 months (OR 1.47 [0.81-2.68]) were not significantly different from MTA. The results were similar in the direct pulp capping subgroup, whereas, in the partial and full pulpotomy subgroup, there was not enough evidence to achieve significant differences. MTA, Biodentine, and Totalfill are the most efficient materials for VPT. However, calcium-hydroxide-based materials are not recommended in VPT. [ABSTRACT FROM AUTHOR]

The combination of multiple factors in marine environments can accelerate the concrete corrosion. In this work, bending fatigue load, dry–wet cycles and Cl− erosion were experimentally combined to evaluate the endurance of marine concrete incorporating nanoparticles (nano-silica (NS) and nano-titania (NT)). Dry–wet cycles of the nano-concretes were simulated in seawater (5% sodium chloride solution) and bending fatigue loads at stress levels of 0.5, 0.6, 0.7 and 0.8 were applied. The results indicated that the nanoparticles enhanced the resistance to Cl− erosion during dry–wet cycles and bending fatigue load by making the concrete more durable under coupled bending fatigue load, dry–wet cycles and Cl− erosion. The improvements were the most obvious for a NT content of 1% and a NS content of 2%, and the improvement was better with 1% NT than with 2% NS content is 2%. The free Cl− content in the concrete tension zone was larger than in the compressive zone. X-ray diffraction was used to assess the physical phases of the concretes before and after the experiments and to analyse the reasons for the increased concrete durability. The nanoparticles increases the content of hydrated calcium silicate in concrete, changed the orientation of calcium hydroxide and improved the concrete durability. [ABSTRACT FROM AUTHOR]

Grouting engineering is extensively employed in highway maintenance, tunnel excavation, mining, and other domains. As application scenarios become more complex, the demands for injectivity and toughness of grouting materials escalate. This research presents the fabrication of a dual-network cementitious material through acrylamide (AM) monomers in-situ polymerization and ultra-fine portland cement for grouting. The in-situ polymerization of AM increases the fluidity of cement paste, forms a hydrogel three-dimensional network structure, and significantly reduces the initial setting time from 345 to 35 min at a 5% AM content. The early-stage compressive strength (0–7 days) is inhibited by the in-situ polymerization, the flexural strength is notably increased, with an overall toughness improvement of 174.4% at a 7% AM content. The in-situ polymerization influences the early hydration behavior of ultra-fine portland cement by delaying the hydration induction period and affecting calcium hydroxide content and the bound water in calcium silicate hydrate. The complexation between metal ions (Ca2+, Al3+) in ultra-fine portland cement and carboxyl groups in the polymer enhances organic–inorganic interaction. The three-dimensional network structure of the cement hydration products and the polymer will form a dual-network structure, further enhancing the performance of the ultra-fine portland cement. In this research, the potential application of AM in-situ polymerization in the enhancement of ultra-fine portland cement grouting is proposed. [ABSTRACT FROM AUTHOR]

In recent years, inorganic nanoparticles, including calcium hydroxide nanoparticles [Ca Ca(OH)2 NPs], have attracted significant interest for their ability to impact plant photosynthesis and boost agricultural productivity. In this study, the effects of 15 and 30 mg L−1 oleylamine-coated calcium hydroxide nanoparticles [Ca(OH)2@OAm NPs] on photosystem II (PSII) photochemistry were investigated on tomato plants at their growth irradiance (GI) (580 μmol photons m−2 s−1) and at high irradiance (HI) (1000 μmol photons m−2 s−1). Ca(OH)2@OAm NPs synthesized via a microwave-assisted method revealed a crystallite size of 25 nm with 34% w/w of oleylamine coater, a hydrodynamic size of 145 nm, and a ζ-potential of 4 mV. Compared with the control plants (sprayed with distilled water), PSII efficiency in tomato plants sprayed with Ca(OH)2@OAm NPs declined as soon as 90 min after the spray, accompanied by a higher excess excitation energy at PSII. Nevertheless, after 72 h, the effective quantum yield of PSII electron transport (ΦPSII) in tomato plants sprayed with Ca(OH)2@OAm NPs enhanced due to both an increase in the fraction of open PSII reaction centers (qp) and to the enhancement in the excitation capture efficiency (Fv'/Fm') of these centers. However, the decrease at the same time in non-photochemical quenching (NPQ) resulted in an increased generation of reactive oxygen species (ROS). It can be concluded that Ca(OH)2@OAm NPs, by effectively regulating the non-photochemical quenching (NPQ) mechanism, enhanced the electron transport rate (ETR) and decreased the excess excitation energy in tomato leaves. The delay in the enhancement of PSII photochemistry by the calcium hydroxide NPs was less at the GI than at the HI. The enhancement of PSII function by calcium hydroxide NPs is suggested to be triggered by the NPQ mechanism that intensifies ROS generation, which is considered to be beneficial. Calcium hydroxide nanoparticles, in less than 72 h, activated a ROS regulatory network of light energy partitioning signaling that enhanced PSII function. Therefore, synthesized Ca(OH)2@OAm NPs could potentially be used as photosynthetic biostimulants to enhance crop yields, pending further testing on other plant species. [ABSTRACT FROM AUTHOR]

Biodiesel, an eco-friendly alternative to conventional fossil fuels, offers reduced emissions like carbon dioxide, sulfur oxides, and soot. This study explores biodiesel production from a blend of waste oils using a novel biomass-based catalyst derived from the bottom ash of a biomass boiler. Catalyst synthesis involved wet impregnation, a unique approach using previously unreported bottom ash. Characterization via SEM-EDS, BET, FTIR, and XRD revealed its composition and structure. Optimization of biodiesel production involved assessing alcohol molar ratio, catalyst concentration, and reaction time, achieving a maximum FAME concentration of 95% under specific conditions. Blending residual palm oil with waste frying oil enhanced biodiesel properties, demonstrating a maximum FAME concentration at specific catalyst concentration (8%), molar ratio (1:10), and reaction time (2 h). Catalyst reusability, up to three cycles without significant yield variation, showcased its sustainability. The catalyst, primarily composed of calcium, a characteristic biomass bottom ash component, exhibited mesoporous features. Impregnation with eggshells not only altered composition but also ensured a uniform particle size distribution. FTIR and XRD analyses indicated calcium in hydroxide and crystallized forms. Effective catalyst separation methods included decanting or water washing, with optimal biodiesel purity achieved through 3% phosphoric acid washing at 60 °C. Various recovery methods were assessed, highlighting hexane washing as the most efficient, enabling up to three catalyst reuse cycles without substantial efficiency loss. [ABSTRACT FROM AUTHOR]

Thermochemical energy storage (TCES) presents a promising method for energy storage due to its high storage density and capacity for long-term storage. A combination of TCES and district heating networks exhibits an appealing alternative to natural gas boilers, particularly through the utilisation of industrial waste heat to achieve the UK government's target of Net Zero by 2050. The most pivotal aspects of TCES design are the selected materials, reactor configuration, and heat transfer efficiency. Among the array of potential reactors, the fluidised bed emerges as a novel solution due to its ability to bypass traditional design limitations; the fluidised nature of these reactors provides high heat transfer coefficients, improved mixing and uniformity, and greater fluid-particle contact. This research endeavours to assess the enhancement of thermochemical fluidised bed systems through material characterisation and development techniques, alongside the optimisation of heat transfer. The analysis underscores the appeal of calcium and magnesium hydroxides for TCES, particularly when providing a buffer between medium-grade waste heat supply and district heat demand. Enhancement techniques such as doping and nanomaterial/composite coating are also explored, which are found to improve agglomeration, flowability, and operating conditions of the hydroxide systems. Furthermore, the optimisation of heat transfer prompted an evaluation of heat exchanger configurations and heat transfer fluids. Helical coil heat exchangers are predominantly favoured over alternative configurations, while various heat transfer fluids are considered advantageous depending on TCES material selection. In particular, water and synthetic liquids are compared according to their thermal efficiencies and performances at elevated operating temperatures. [ABSTRACT FROM AUTHOR]

The physicochemical properties of steel slag were investigated using SEM and IR, and it was found that free calcium oxide and free magnesium oxide in steel slag produce calcium hydroxide when in contact with water, leading to volume expansion. Thus, the expansion rate of steel slag itself was first investigated, and it was found that the volume expansion of steel slag was more obvious in seven days after water immersion. Then, the cement dosages of 5% and 6% of the steel slag expansion rate and cement-stabilized gravel volume changes between the intrinsic link were further explored after the study found that the cement bonding effect can be partially inhibited due to the volume of expansion caused by the steel slag, so it can be seen that increasing the dosage of cement can reduce the volume expansion of steel slag cement-stabilized gravel with the same dosage of steel slag. Finally, a prediction model of the expansion rate of steel slag cement-stabilized gravel based on the BP (back propagation) neural network was established, which was verified to be a reliable basis for predicting the expansion rate of steel slag cement-stabilized aggregates and improving the accuracy of the proportioning design. [ABSTRACT FROM AUTHOR]

This study provides experimental insights into the optimization of alkali-activated materials (AAMs) carried out in situ at the restoration site of Monreale Cathedral, Italy. Volcanic ash from Mt. Etna volcano (Italy) was used as a precursor to obtain AAMs. Standard and modified pastes with a small amount of slaked lime paste were compared in terms of setting time, rheology, mineralogy, chemical morphology, and mechanical performance. The modified pastes exhibited a faster setting time, superior mechanical strength and rheological properties. Mineralogically, no difference was observed between the two pastes for the small amount of slaked lime paste added very close to the detectable limit (<2 wt%). Moreover, its addition causes slight differences in the morphology of the gel without changing the chemical composition of the Na 2 O–CaO–Al 2 O 3 –SiO 2 –H 2 O ((N,C)-A-S-H)) type. The results obtained may be useful for the development and optimization of building materials (especially for restoration purposes) where appropriate physico-mechanical performance is required. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Azathioprine is one of the earliest immunosuppressants prescribed for several autoimmune diseases. Yet there is a lack of research on the impact of azathioprine on pulp healing following the pulp capping procedure. Aim: This study aimed to investigate the effect of azathioprine on the healing ability of mechanically exposed dogs' dental pulps following direct pulp capping with mineral trioxide aggregate (MTA), bio-aggregates (BA), and Calcium hydroxide (Ca(OH)2). Methods: Four mongrel dogs were randomly assigned to two groups (two dogs/30 teeth in each group): immunosuppressed (group I) and control (group II). Group I received azathioprine for two months before surgical treatments and until the dogs were euthanized. Fifteen class V buccal cavities were performed in each dog. Each group was randomly divided into three subgroups (10 teeth each) based on the pulp capping substance. The pulps in subgroups A, B, and C were immediately capped with MTA, BA, and Ca(OH)2, respectively. Inflammation and dentine bridge development were histopathologically evaluated and scored at one and two months. The data were statistically analyzed. Results: The immunosuppressed group exhibited statistically greater inflammatory cell count and decreased dentine bridge thickness, compared to the control group in all subgroups (p < 0.05). Conclusion: Azathioprine has an adverse effect on the healing of exposed dogs' dental pulp following direct pulp capping with MTA, BA, and Ca(OH)2. Therefore, patients using azathioprine as an immunosuppressive medication may experience delayed healing of mechanically exposed pulps following capping with MTA, BA, or Ca(OH)2. [ABSTRACT FROM AUTHOR]

Porous ceramics were synthesized using porcelain tile polishing residue (PTPR) and slaked lime (Ca(OH)2) as a reinforcing agent through a hydrothermal autoclaving method. The process parameters, including the quantity of slaked lime added, the hydrothermal autoclaving temperature, and the reaction duration, were optimized meticulously. The composition, structure, thermal and physical properties of the samples were thoroughly analyzed via Brunauer–Emmett–Teller (BET) measurements, powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The results indicated that the incorporation of slaked lime and hydrothermal autoclaving led to the formation of calcium silicate hydrate, which corresponded with an enhancement in the strength of the sample. Notably, when the quantity of slaked lime added was optimized at 30 wt%, the formation of tobermorite (5CaO·6SiO2·5H2O) was detected. At a hydrothermal autoclaving temperature of 150 °C, the formation of only sheet-like calcium silicate hydrate was observed. In contrast, at an elevated temperature of 180 °C and 210 °C, needle-like tobermorite was successfully synthesized. The porous ceramic with the most favorable structure was obtained through autoclaving at 180 °C for 10 h with 30 wt% slaked lime, exhibiting a total pore volume of 0.11 mL/g, a specific surface area of 26.35 m2/g, and a mesoporous volume fraction of 90.40%. [ABSTRACT FROM AUTHOR]

Aim: Design, produce and assess the viability of a novel nanotechnological antibacterial thermo‐sensible intracanal medicament This involves encapsulating calcium hydroxide (Ca(OH)2) within polylactic‐co‐glycolic acid (PLGA) nanoparticles (NPs) and dispersing them in a thermosensitive gel (Ca(OH)2‐NPs‐gel). In addition, perform in vitro and ex vivo assessments to evaluate tissue irritation and penetration capacity into dentinal tubules in comparison to free Ca(OH)2. Methodology: Reproducibility of Ca(OH)₂‐NPs was confirmed by obtaining the average size of the NPs, their polydispersity index, zeta potential and entrapment efficiency. Moreover, rheological studies of Ca(OH)2‐NPs‐gel were carried out with a rheometer, studying the oscillatory stress sweep, the mean viscosity value, frequency and temperature sweeps. Tolerance was assessed using the membrane of an embryonated chicken egg. In vitro Ca(OH)2 release was studied by direct dialysis in an aqueous media monitoring the amount of Ca(OH)2 released. Six extracted human teeth were used to study the depth of penetration of fluorescently labelled Ca(OH)2‐NPs‐gel into the dentinal tubules and significant differences against free Ca(OH)2 were calculated using one‐way anova. Results: Ca(OH)2‐NPs‐gel demonstrated to be highly reproducible with an average size below 200 nm, a homogeneous NPs population, negative surface charge and high entrapment efficiency. The analysis of the thermosensitive gel allowed us to determine its rheological characteristics, showing that at 10°C gels owned a fluid‐like behaviour meanwhile at 37°C they owned an elastic‐like behaviour. Ca(OH)2‐NPs‐gel showed a prolonged drug release and the depth of penetration inside the dentinal tubules increased in the most apical areas. In addition, it was found that this drug did not produce irritation when applied to tissues such as eggs' chorialantoidonic membrane. Conclusion: Calcium hydroxide‐loaded PLGA NPs dispersed in a thermosensitive gel may constitute a suitable alternative as an intracanal antibacterial medicament. [ABSTRACT FROM AUTHOR]

Calcium Hydroxide-based endodontic sealer loaded with antimicrobial agents have been commonly employed in conventional root canal treatment. These sealers are not effective against E. faecalis due to the persistent nature of this bacterium and its ability to evade the antibacterial action of calcium hydroxide. Therefore, endodontic sealer containing Carbon nanodots stabilized silver nanoparticles (CD-AgNPs) was proposed to combat E. faecalis. The therapeutic effect of CD-AgNPs was investigated and a new cytocompatible Calcium Hydroxide-based endodontic sealer enriched with CD-AgNPs was synthesized that exhibited a steady release of Ag+ ions and lower water solubility at 24 hours, and enhanced antibacterial potential against E. faecalis. CD-AgNPs was synthesized and characterized morphologically and compositionally by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, followed by optimization via minimum inhibitory concentration (MIC) determination against E. faecalis by broth microdilution technique and Cytotoxicity analysis against NIH3T3 cell lines via Alamar Blue assay. Calcium hydroxide in distilled water was taken as control (C), Calcium hydroxide with to CD-AgNPs (5mg/ml and 10mg/ml) yielded novel endodontic sealers (E1 and E2). Morphological and chemical analysis of the novel sealers were done by SEM and FTIR; followed by in vitro assessment for antibacterial potential against E. faecalis via agar disc diffusion method, release of Ag+ ions for 21 days by Atomic Absorption Spectrophotometry and water solubility by weight change for 21 days. CD-AgNPs were 15–20 nm spherical-shaped particles in uniformly distributed clusters and revealed presence of constituent elements in nano-assembly. FTIR spectra revealed absorption peaks that correspond to various functional groups. UV-Vis absorption spectra showed prominent peaks that correspond to Carbon nanodots and Silver nanoparticles. CD-AgNPs exhibited MIC value of 5mg/ml and cytocompatibility of 84.47% with NIH3T3 cell lines. Novel endodontic sealer cut-discs revealed irregular, hexagonal particles (100–120 nm) with aggregation and rough structure with the presence of constituent elements. FTIR spectra of novel endodontic sealers revealed absorption peaks that correspond to various functional groups. Novel endodontic sealers exhibited enhanced antibacterial potential where E-2 showed greatest inhibition zone against E. faecalis (6.3±2 mm), a steady but highest release of Ag+ ions was exhibited by E-1 (0.043±0.0001 mg/mL) and showed water solubility of <3% at 24 hours where E-2 showed minimal weight loss at all time intervals. Novel endodontic sealers were cytocompatible and showed enhanced antibacterial potential against E. faecalis, however, E2 outperformed in this study in all aspects. [ABSTRACT FROM AUTHOR]

Recent research has increasingly focused on synthesizing nanoparticles (NPs) through various methods to determine how these processes influence their characteristics, and consequently, their biological activity. Calcium zinc hydroxide dihydrate (CaZn2(OH)6·2H2O) nanoparticles, designates as CZ, were obtained via sol–gel (CZ-SG), hydrothermal (CZ-HT), and microwave (CZ-MW) methods, and their properties were characterized using XRD, SEM, TEM, and BET analyses. The different synthesis revealed distinct CZ nanoparticle attributes, including variations in crystallite sizes (72 nm for CZ-SG, 65 nm for CZ-HT and CZ-MW) and morphologies (fibrous for CZ-HT and spherical agglomerates for CZ-SG and CZ-MW). Surface area analysis showed low values across all synthesis methods, with CZ-HT exhibiting the best surface area (8.154 m2/g). The investigation also explored how these synthesis routes influence antifungal efficacy against fourteen fungal strains associated with the biodeterioration of limestone cultural heritage structures. Our results highlight the notable antifungal activity of CZ-NPs, particularly those synthesized via the CZ-HT method, which demonstrated the most effective antifungal action as evidenced by the lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). This effectiveness is attributed to the unique fibrous morphology, which proves to be highly inhibitory to fungal cell proliferation. These findings not only advance our understanding of CZ NPs-mediated antifungal mechanisms but also open a new effort for the development of effective preservation strategies for cultural heritage conservation. [ABSTRACT FROM AUTHOR]

• Single and dual nanoparticle-based treatments are used for preserving materials. • Hardness and erosion properties were improved using these nanoparticles (NPs). • A new C-S-H cementing gel is formed when Ca(OH)2/SiO2 NPs are combined. • The NPs did not significantly alter water vapour permeability. • ΔE was suitable in all cases (0.40–3.79), except for Ca-NPS (5.10). This paper studies the effectiveness of four consolidation treatments based on nanoparticles suspensions: calcium hydroxide (Ca-NP), magnesium hydroxide (Mg-NP), a treatment combining calcium hydroxide and magnesium hydroxide (Ca/Mg-NP), and a treatment consisting of calcium hydroxide and silicon dioxide (Ca/Si-NP) that were both applied separately. The suspensions were sprayed on gypsum plasters and lime renders which are common substrates in historical constructions and show a high degree of similarity with the treatments. The consolidation efficiency was evaluated using non-destructive techniques, such as peeling test, Shore-D hardness, water flow using Karsten tube and water vapour permeability tests. In addition, TEM images and XRD tests demonstrated the formation of a new C-S-H cementing phase when Ca/Si-NPs were combined due to a reaction between Ca(OH) 2 with SiO 2. Colour tests (CIE-L*a*b*) showed the consolidants did not produce major colour alterations, although the Ca-NP treatment caused a slight lightness increase. The strengthening effect was greater in lime mortars and water flow was moderately reduced in all treatments, except in mortars coated with Ca/Mg-NP. Finally, the chemical nature of the treatments is similar to the substrates, and they did not significantly alter the water vapour permeability of the studied materials. [ABSTRACT FROM AUTHOR]

Herein, a new template carbonization method is used to prepare calcite‐type nano‐calcium carbonate (CaCO3) with a core–shell structure using calcium hydroxide as a solute and Pluronic F‐127 as a templating and pore‐forming agent. Dopamine hydrochloride is added to control the size of calcium hydroxide particles. The morphology, particle size, and crystal type of CaCO3 are characterized via transmission electron microscopy, X‐ray diffraction, nanoparticle size, and zeta potentiometer. The creation of core–shell calcium carbonate nanoparticles is examined in relation to reaction circumstances (i.e., additive sequence, additive amount, and additive mixing time), carbonization temperature, liquid flow rate, and templates with varying chain lengths. Furthermore, a discussion is held regarding the formation mechanism of spherical core–shell calcium carbonate that is created using the innovative template carbonization method. The results show that the order, amount, liquid flow rate, and template type of additives have a significant effect on the crystal shape of calcium carbonate nanoparticles. The mixing time of additives has a significant effect on the particle size of calcium carbonate nanoparticles. Interestingly, the thickness of the shell depends on the carbonization temperature, and too slow or too fast flow rate will lead to the formation of cyclic calcium carbonate nanoparticles. [ABSTRACT FROM AUTHOR]

Objectives: This randomized clinical trial aimed to compare the effect of intracanal medicaments on the incidence of postoperative pain and flare-up with posttreatment apical periodontitis (PTAP) of retreatment cases. Materials and methods: One hundred twenty patients diagnosed with PTAP with single-rooted teeth with single-canal without spontaneous pain or swellings were included and randomly divided into three groups according to the intracanal medicament used. Intracanal medicaments were placed into the root canals following the removal of previous root canal fillings and re-instrumentation. Calcium hydroxide (Ca (OH)2), chlorhexidine gel (CHX), calcium hydroxide and chlorhexidine gel combinations were used as intracanal medicaments. Postoperative pain scores were recorded at 6 and 12 h and 1, 2, 3, 4, 5, 6, and 7 days using a visual analog scale (VAS). Sensitivity on percussion, spontaneous pain, swelling, antibiotic and analgesic requirements of the patients were evaluated during clinical examinations performed postoperatively after 2 and 7 days. Results: There were no statistically significant differences between groups in terms of VAS scores following the intracanal medicament application (p > 0.05). However, compared to the patients of 20–34 and 50–65 age groups, greater VAS scores were observed in patients of 35–49 age groups at 12 h, and 3, 4, 7 days (p < 0.05). Flare-up was observed in only one patient in the CHX gel group, and no flare-up was observed in other groups. Conclusions: Similar postoperative pain incidence in all experimental groups indicates that all three medicaments are clinically acceptable in inter-appointment management of retreatment cases in terms of post-endodontic pain and flare-up. Clinical relevance: In this randomized clinical trial, three different intracanal medicaments were utilized in nonsurgical endodontic retreatment and their effect on postoperative pain and flare-up incidence was examined. Thus, this study will be a significant contribution in the decision-making during clinical practice; since there are a limited number of prospective clinical trials in the literature about the severity of pain following retreatment procedures including intracanal medicament use. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effectiveness of Er:YAG laser-activated irrigation (LAI) with a short pulse duration for removing calcium hydroxide (CH) from simulated internal root resorption (IRR) cavities at three root levels. Background: Pulse duration is an important parameter during LAI, which ensures the efficiency of irradiation and the corresponding activation process. Short pulses in the range of a few microseconds enable rapid expansion and successive implosion of irrigants, resulting in distinct fluid movement. There have been few reports on CH removal efficacy from IRR cavities of different LAI systems, including those using short pulse duration. Methods: IRR cavities (1.6 mm diameter) were created at the apical, middle, and coronal root levels in 60 mandibular premolars and filled with a radiopaque CH paste. Samples were assigned to the following irrigation groups (n = 12, each): (1) LAI(P)-F, a prototype laser device that operates with short pulse duration (Morita Manufacturing) with a flat tip; (2) LAI(EA)-F, the ErwinAdverl laser device (Morita Manufacturing) with a flat tip; (3) LAI(EA)-T, the ErwinAdverl laser device with a tapered tip; (4) PIPS-T, the Lightwalker laser device (Fotona) with a tapered tip; and (5) SI, the syringe irrigation group. The laser tips were fixed at the canal entrance. The remaining CH volume and surface area were assessed in IRR cavities using micro-computed tomography and scanning electron microscopy, respectively. Data were statistically analyzed utilizing one-way analysis of variance and Tukey’s test at 5% significance level. Results: The LAI(P)-F and PIPS-T groups exhibited the highest CH removal rates at three different levels (p < 0.05). The LAI(EA)-F group had a significantly better efficacy of CH removal compared with the LAI(EA)-T group at the middle level (p < 0.05). Conclusion: The LAI(P)-F and PIPS-T groups demonstrated superior efficiency in removing CH from simulated IRR cavities. [ABSTRACT FROM AUTHOR]

Microbial self-healing concrete (MSHC) is an eco-friendly material that supports low-carbon development. However, the formation mechanism of calcium carbonate (CaCO3) in MSHC remains unclear. This study investigated the formation process of CaCO3 clusters in MSHC using molecular simulation. The hydroxide ion and carbonate ion (CO32−) would compete for association with calcium ion in MSHC. The formation process of CaCO3 clusters could be summarised as follows: free ions first associated to form ion pairs, then ion pairs aggregated into small clusters through ion-dipole interactions, and finally, small clusters overcame the surface charge effect by high-frequency aggregation-separation behaviour to transform into large clusters and further densify themselves. The reaction rate of CaCO3 cluster formation decreased significantly with the decrease of CO32− concentration, and the association between calcium ion and hydroxide ion would dominate when the CO32− concentration was low. [ABSTRACT FROM AUTHOR]

Objectives: The mannose phosphotransferase system (Man-PTS) plays crucial roles in the adaptive metabolic activity of Enterococcus faecalis (E. faecalis) in adverse environments. The aim of this study was to evaluate the role of Man-PTS in the alkaline resistance of E. faecalis against calcium hydroxide (CH) and the effect of metformin (Met) on the alkaline resistance of E. faecalis to CH. Materials and methods: The regulatory role of Man-PTS EII in the alkaline resistance of E. faecalis was firstly investigated using a wild-type highly alkaline-resistant E. faecalis XS 003, standard ATCC 29212 and Man-PTS EIID gene deficient (△mptD) and overexpressing (+mptD) strains of E. faecalis. RNA sequencing of Met-treated E. faecalis was performed to further validate the effect of Met on Man-PTS. The effect of Met on CH resistance of E. faecalis was verified by evaluating the survival, membrane potential and permeability, intracellular pH and ATP, and the expression of Man-PTS EII and membrane transporter-related genes of E. faecalis. The effect of Met on the ability of CH to remove E. faecalis biofilm on the dentin surface was also tested. The in vivo therapeutic effect of Met plus CH (CHM) was further investigated in a rat apical periodontitis model induced by E. faecalis XS 003. Results: Man-PTS EII significantly promoted the survival ability of E. faecalis in CH and enhanced its resistance to CH. The inhibition of Man-PTS EII by Met resulted in reduced alkaline resistance of E. faecalis in the presence of CH, while also enhancing the antimicrobial properties of CH against E. faecalis biofilm on dentin. Additionally, Met plus CH showed the synergistically promoted intra-canal E. faecalis infection control and healing of periapical lesion in rats. Conclusions: Met could significantly reduce the alkaline resistance of E. faecalis against CH through the modulation of Man-PTS EII, and improved the antibacterial effect of CH against E. faecalis infection both in vitro and in vivo. Clinical relevance: Met could significantly enhance the ability of CH to control E. faecalis infection through reducing the alkaline resistance of E. faecalis. [ABSTRACT FROM AUTHOR]

Room temperature–cured alkali-activated binders of enhanced strength are produced without external silica addition. The extraction of nanosilica and its use in producing alkali-activated binders made of fly ash and slag are explored. Low-energy extraction of an aqueous nanosilica activating solution is developed in a zero-waste utilization process. Alkali-activated slag–fly ash (AASF) binders are activated with alkaline fly ash–based aqueous nanosilica (FABANS) solutions. FABANS is highly amorphous nanosilica extracted from fly ash through dissolution in an alkaline solution that also activates the slag. The reaction kinetics, compressive strength, and reaction products are evaluated in an AASF made with alkaline FABANS. There is a significant strength improvement from the enhanced formation of calcium aluminosilicate hydrate (C─ A─ S─ H) gel and densification of the microstructure in AASF made with FABANS. The Na in the activated AASF binder is recovered by water leaching. The setting and strength gain in the AASF are due to slag hydration. Using FABANS efficiently mobilizes the reactive silica from fly ash to enhance reaction product formation in AASF. FABANS is suitable for enhancing the strength of concrete produced with AASF binders achieved at room temperature. [ABSTRACT FROM AUTHOR]

Gypsification is a common problem in weathered calcareous relics. In previous studies, the solutions of barium hydroxide in water and methanol were used as protectants for gypsification calcareous relics and showed significant differences in permeability. In this study, the underlying reasons for permeability differences between these two solutions were investigated using optical microscopy, ultraviolet–visible spectrophotometry, X-ray diffractometry, Fourier transform infrared spectroscopy, the phenolphthalein test and physical property characterizations. The results indicated that the permeability differences were primarily caused by the solutions' reactivity. Specifically, owing to the high reactivity of barium hydroxide in water, it reacted rapidly with atmospheric CO2 and gypsum (the weathering product) to generate barium carbonate, barium sulfate and calcium hydroxide precipitates. These precipitates hindered the penetration of solution into weathered relics. In contrast, barium hydroxide in methanol did not react with atmospheric CO2 or weathered relics, which also kept the solution in a liquid state during the infiltration process. Therefore, the solution of barium hydroxide in methanol exhibited high permeability. Based on the above findings, this study is meaningful for applying barium protectants in the conservation of gypsification calcareous relics. [ABSTRACT FROM AUTHOR]

Lime (which exists as calcium oxide and calcium hydroxide) is typically obtained by calcinating limestone, which consists of calcium carbonate. The process releases large amounts of carbon dioxide (CO2) into the atmosphere. Calcium hydroxide (Ca(OH)2) may also be obtained by treating calcium carbonate or calcium sulphate with an alkaline aqueous solution. These processes generate Ca(OH)2 without calcinating limestone, thereby avoiding the emission of CO2. However, the use of alkaline chemicals may still be accompanied by a carbon footprint associated with the manufacturing process (for example, using electricity generated through the combustion of fossil fuels). In this study, we produced Ca(OH)2 using gypsum (calcium sulphate dihydrate) powder and wastewater containing a small amount of sodium hydroxide (NaOH). Our method constitutes an environmentally responsible process for producing lime, using resources harvested from demolishing buildings and returnable bottle-washing processes. Our results demonstrate that a small amount of NaOH in an aqueous solution can effectively transform gypsum into Ca(OH)2 and that the composition of Ca(OH)2 and gypsum can affect the NaOH content and reaction time. We establish a process for transforming wastewater treatment into resource recovery, producing lime in an environmentally responsible manner and augmenting the construction of a carbon-neutral society. [ABSTRACT FROM AUTHOR]

Introduction: The material for exposed pulp treatment is calcium hydroxide (Ca(OH)2), although there are still some disadvantages. Composites with components of gelatin, chitosan, carbonated hydroxyapatite, and Tetraethyl orthosilicate (TEOS) were used to develop the material to obtain optimal quality. Nestin is a marker for differentiation of odontoblast and expressed in irritated odontoblasts. This study evaluated Nestin expression in the dental pulp after applying gelatin-chitosan-TEOS-Ca(OH)2 composite material. Materials and methods: There were 30 Wistar rats divided into two groups, namely the treatment and control groups, with 15 rats in each group. The maxillary first molar tooth was opened using diamond bur No. 010 to the depth of the pulp. The gelatin-chitosan-TEOS-Ca(OH)2 composite was applied in the treatment group, while the control group used Ca(OH)2, followed by temporary fillings. The expression of Nestin was evaluated after 1,3,5,7, and 14 days of application using immunohistochemistry method under light microscopy with 64x and 160x magnifications. Three replication was taken for each evaluation time. Results: A positive expression seen in both the treatment and control groups. The pulp area beneath the irritated tissue showed positive expression of Nestin, especially in the odontoblasts and their processes, pulp cells near positive of the odontoblasts, and flat cells attached to the dentin. The treated group showed weaker Nestin expression than the control group. Conclusion: The gelatin-chitosan-TEOS-Ca(OH)2 composite material has potential as an exposed pulp medicament. After applying the gelatin-chitosan-TEOS-Ca(OH)2 composite to the exposed pulp, the positive Nestin expression indicates a pulp tissue regeneration process. [ABSTRACT FROM AUTHOR]

This article explores the phenomenon of the Coke-Mentos fountain and aims to determine if the released carbon dioxide can be quantified using traditional methods. Two methods, pneumatic collection and gravimetric determination, are used to analyze Coca-Cola Light. The results show that more carbon dioxide is released in Coca-Cola Light compared to Coca-Cola Classic. The article discusses different approaches to quantifying the fountain and highlights the importance of controlling variables in experiments. The text concludes with recommendations for further research to explore the influence of different cola varieties on carbon dioxide release. The authors are researchers and educators in the field of chemistry. [Extracted from the article]

The viability of incorporating agricultural by-products, such as oat husks, not yet explored in limestone-based composites, as more sustainable alternatives for use as novel aggregates may be improved through the adoption of well-known valorisation strategies applied to other plant-based resources. In this context, this work innovates by assessing how treatments on oat husk surfaces and the choice of limestone-based binders impact the mechanical performance of composites. The strategy adopted to achieve these objectives, in addition to carrying out the physical and geometric characterisation of the husks, consists of treating the husks' surface using washing cycles in water, cement/pozzolan binder, and linseed oil. Furthermore, matrices combining cement, calcium hydroxide Ca(OH)2, and microsilica (SiO2) were used. In conclusion, even though the effects of different binder combinations are inconsistent, coating oat husks—especially with linseed oil—works well in delaying particle degradation and improving mechanical strength compared to untreated particles. Furthermore, when aggregates are substituted with the longer and lamellar particles of oat husk, the impact of the water/cement ratio on mechanical performance and composite workability significantly decreases. [ABSTRACT FROM AUTHOR]

Molybdenum tailings are accumulated in large quantities, occupying the land and polluting the environment. Therefore, the resource utilization of molybdenum tailings is imperative. In this paper, the influence of molybdenum tailings powder (MTs) as admixture on hydration characteristics, including hydration heat, hydration products, phase composition, and mechanical properties evolution of cement paste were investigated. Results showed that the early hydration of cement paste can be promoted when the content of MTs is not more than 15%. The compressive strength of cement paste with 15% MTs at 3, 28, and 120 days was 89.37%, 96.14%, and 91.68% of that of the portland cement (PC) group, respectively. When the content of MTs does not exceed 15%, the second exothermic peak of hydration heat of cement paste appears ahead of time and the peak value increases. With the increase of MTs content, the cumulative heat release of 72 h gradually decreased. The addition of MTs does not produce new hydration products, but introduces the mineral phase of MTs itself, and leads to the early transformation of ettringite (AFt) into monosulfoaluminate (AFm) in paste. There is still a close linear relationship between the compressive strength and cumulative heat release and chemically bound water content after addition of MTs into cement paste. It was also discovered that the pozzolanic activity of MTs in cement paste mainly occurred from 3 to 28 days. After 28 days, the particle-filling effect of MTs was dominant mainly. The research results are expected to provide basic research for the resource utilization of MTs. [ABSTRACT FROM AUTHOR]

It is important to study the steel corrosion inhibition behavior in complex chloride salt environments. This paper uses the fact that calcined layered double hydroxides (CLDHs) have a certain memory effect, which means that it can reabsorb water and anions and partially restore the lamellar structure under certain conditions. This work investigated the influence of cation types on the steel corrosion inhibition behavior of CLDH in saturated calcium hydroxide solution using equilibrium isotherms of Cl− uptake, the electrochemical method, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscopy (SEM) techniques. The results show that the corrosion inhibition of the CLDH is affected by the cation types in the following order: Ca2+>Mg2+>K+≈Na+·Na+ and K+ increase the pH of the solution and decrease the corrosion inhibition of CLDH. The addition of Mg2+ can promote the reconstruction of Mg-Al-Zn-Cl hydrotalcite. The addition of Ca2+ can promote the formation of new Ca-Al layered double hydroxide (Ca-Al-LDH) and improve the corrosion inhibition. [ABSTRACT FROM AUTHOR]

The mechanical properties and early autogenous shrinkage of ultra-high-performance concrete (UHPC) were experimentally investigated with the incorporation of magnesium oxide expansive agent (MEA) and nano-silica (NS). XRD and SEM were conducted to analyze the early hydration reactions and hydration products. The results indicate that the addition of MEA and NS both reduces the flowability of UHPC, and their combined incorporation further decreases flowability. The introduction of MEA decreases the compressive strength of UHPC at different ages, while the addition of appropriate amounts of NS and MEA significantly improves both compressive strength and early autogenous shrinkage of UHPC. Microscopic tests using XRD and SEM reveal that NS effectively reduces the content of calcium hydroxide in the UHPC system. The UHPC with 0.5 % NS and 6.0 % MEA has a denser structure and no obvious macropores and flake calcium hydroxide, which makes the UHPC have good volume stability and mechanical properties. [ABSTRACT FROM AUTHOR]

The hatch rate of chick embryos cultured outside of the eggshell with 350 mg calcium l‐lactate hydrate (CaL) and 3.5 mL water is fourfold greater in cultures in which the chorioallantoic membrane (CAM) surrounds the egg contents by incubation day 17.5 (E17.5) an event which occurs in ovo by E13. It was first investigated whether decreasing the volume of water added with 350 mg CaL would promote CAM expansion due to the smaller volume to enclose. When 350 mg CaL was present, the CAM did not surround the egg contents by E13. By E17.5, the CAM surrounded the egg contents in 53%–74% of cultures; however, CAM expansion was not significantly different when 0, 1, 2, or 3.5 mL water was present. The hatch rate with 2 or 3.5 mL water was greater than 50% but was not improved with less water. Second, it was investigated whether CaL or water inhibits CAM expansion. In the absence of CaL, the CAM surrounded the egg contents in up to two‐thirds of cultures by E13, whether 2 mL water was present or not. Thus CaL, but not water, inhibits expansion of the CAM by E13, even though CaL promotes hatching. Finally, it was investigated whether injection of aqueous CaL into the allantoic fluid, in conjunction with not adding CaL to culture hammocks, would promote CAM expansion. Allantoic injection of CaL starting at E13 did not promote CAM expansion at E17.5 but resulted in hatch rates of approximately 30%. Allantoic injection is a novel route for supplementation of calcium in cultured chick embryos. Research Highlights: Injection of calcium l‐lactate hydrate (100 mg/mL in H2O) at incubation days 13 and E17.5 into shell‐less chick cultures resulted in a hatch rate of over 30%.Allantoic injection is a novel route by which calcium can be added to cultured embryos. [ABSTRACT FROM AUTHOR]

This study analyses and compares around 650 years of mosaic mortar production spanning the Roman, late Roman and Umayyad periods, at Gerasa/Jerash in Jordan, offering a better understanding of composition, structural features, and manufacturing processes. It assesses the value of optical and electron microscopy examination of morphological and textural features, pore structure using MIP, and composition studies using EDX, XRD, FTIR, TGA, and Raman spectroscopy. The study indicated high density lime adhesive was used compared to other mortars. Wood was used as a fuel when producing the lime and natural fibres were incorporated when manufacturing mortars. Aggregates were primarily calcitic with a small proportion of silica-based aggregates. Key outcomes of the study conclude that early Roman mortars were of highest quality, which was demonstrated through the careful selection of materials including different stone for lime and tesserae, and differences between layers. Late Roman mortars used the same slaked lime plus fibres and charcoal. Mortars dating from the Umayyad period also had the same higher lime content than late Roman, but higher porosity with fibres and charcoal. In general, the mortars showed slight differences in content and aggregate; different stone for lime and tesserae. The research attests to underlying traditions as well as changes in mortar mixes and methods according to context and time. The resulting data is contextualized within local and regional approaches. [ABSTRACT FROM AUTHOR]

In glass industry, the evolved gases and fumes from burning the gas fuel absorbed in calcium hydroxide to minimize the pollution of environment. After a period of time, the calcium hydroxide fouled with sulphate and carbonate as action of the absorbed SO3 and CO2 gases. Based on our interest to treatment the solid waste materials, this study intended to convert the obtained waste of calcium hydroxide fouled with gases to valuable products. Firstly, this waste was treated with water, caustic soda and acids. The results confirmed the conversion of waste to pure calcium sulfate by treatment with 6 v/v% sulfuric acid. Secondly, the obtained calcium sulfate was reacted with ammonium dihydrogen phosphate solution for preparation of calcium hydroxyapatite (HAp) nanoparticles. The produced HAp sample was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and N2 adsorption measurements. The obtained findings confirmed that the HAp can be produced after calcination at 700 °C, nanorods-like of sizes ranged from 11 to 15 nm and with main surface functional groups of hydroxyapatite. TGA and DTA data indicated that HAp is thermally stable up to 700 °C. Also, the obtained HAp has Ca/P molar ratio of 1.60 and exhibited high total surface area of 146 m2/g with mesoporous structure which make this material can be used in medical and water purification applications. [ABSTRACT FROM AUTHOR]

Normally, the acidic impurities in hemihydrate phosphogypsum (HPG) must be neutralized when HPG is utilized, and a little amount of calcium hydroxide (CH) is the best choice. In this paper, the effects of excessive CH (5 wt.%, 10 wt.%, 15 wt.% and 20 wt.% of HPG) for carbonation curing on the performance of hardened HPG paste were studied. According to the results of macro tests and microanalyses of XRD, TG, SEM-EDS, MIP and N2 physisorption, it could be verified that CaF2, Ca3(PO4)2 and a large amount of nanoscale CaCO3 crystals were produced as a result of neutralization and carbonation, and the compressive strength and the water resistance of carbonated HPG + CH paste were significantly improved due to the effects of nanoscale CaCO3 crystals on pore refinement and the coverage on the surfaces of gypsum crystals of the hardened paste. Therefore, this study suggests a feasible and green method for recycling HPG/PG, with the collaborative effects of neutralization, performance enhancement and reductions in CO2 emissions. [ABSTRACT FROM AUTHOR]

Non-additive factors can significantly affect the crystallization pathways and hydrate phases of calcium oxalate. However, little is known about the mechanisms behind these phenomena. Our research investigated various factors affecting calcium oxalate crystallization in the absence of additives. We show that the formation of calcium oxalate hydrate phase in a supersaturated solution is inconsistent with thermodynamic stability. The metastable calcium oxalate trihydrate (COT) forms at lower concentrations (<1.25 mM), while the stable calcium oxalate monohydrate (COM) forms at intermediate concentrations, and the metastable calcium oxalate dihydrate (COD) forms at higher concentrations (>20 mM). The formation of the hydrate phase also depends on the method of mixing calcium and oxalate solutions. By utilizing an automatic titration apparatus, we show that the hydrate phase can be altered by adjusting either the titration rate of the calcium solution or the stirring speed. In addition, the calcium-to-oxalate ratio is important in determining the initial binding between calcium and oxalate ions. All these factors could be explained by the local concentration of calcium and oxalate upon mixing the solutions. The reduction of local concentration promotes the formation of COT. Thus, the hydrate phase is determined by a combination of thermodynamic and kinetic factors. These results significantly enhance our understanding of the crystallization pathway and hydrate phase selection of calcium oxalate. [ABSTRACT FROM AUTHOR]

• An uniform and effective deacidification method of acidified paper was proposed. • The mechanism of uniform deacidification was elucidated with capillary action. • This method can endow the treated paper with long-lasting aging resistance. • The mechanism of excellent aging resistance was clarified from microstructure. Deacidification is a necessary and urgent means of protecting acidified paper documents. However, the contradiction between deacidification efficiency and uniformity in existing aqueous or organic phase deacidification methods has not been resolved yet, which is mainly attributed to the differences in capillary action of paper on solvents with different polarities. In this work, a strategy of two-phase deacidification was proposed to achieve efficient and uniform deacidification and long-lasting aging resistance. Impregnation of nano magnesium oxide organic dispersion of deacidified paper achieved efficient batch deacidification and sufficient alkali reserve. Using ultrasonic atomization of saturated calcium hydroxide aqueous solution, the penetration of alkaline substances into paper promoted uniform deacidification based on strong capillary action. Meanwhile, microstructural reinforcement of paper fibers was achieved based on the multiple interactions. This method can endow the treated paper with better thermal stability and long-lasting aging resistance. After artificial accelerated aging for 30 d, the treated paper samples still maintained the highest tensile index (18.46 Nm/g), folding endurance (8.5 times), tear index (3.95 mN·m2/g) and displayed negligible chromatic aberration (∆ E = 2.46 ± 0.21). This method greatly extends the lifespan of acidified paper, which has significant value for the protection of paper documents. [Display omitted] [ABSTRACT FROM AUTHOR]

Bimetallic AuCu/SiO2 nanosized catalysts were prepared using the wet chemical reduction technique. From among Au0.1–1.5Cu10/SiO2 catalysts, the Au0.5Cu10/SiO2 catalyst gave the highest yield of calcium lactate of 87% at a glycerol conversion of 96% when the reaction of glycerol with calcium hydroxide at a mole ratio of calcium hydroxide to glycerol of 0.8:1 was conducted under an anaerobic atmosphere at 200 °C for 2 h. The interactions between metallic Au0 and Cu0 nanoparticles facilitate calcium lactate formation. The simulation of glycerol consumption rate with an empirical power-function reaction kinetics equation yielded a reaction activation energy of 44.3 kJ∙mol−1, revealing that the catalytic reaction of glycerol with calcium hydroxide to calcium lactate can be conducted by overcoming a mild energy barrier. The synthesis of calcium lactate through the catalytic reaction of glycerol with calcium hydroxide on a bimetallic AuCu/SiO2 nanosized catalyst under a safe anaerobic atmosphere is an alternative to the conventional calcium lactate production technique through the reaction of expensive lactic acid with calcium hydroxide. [ABSTRACT FROM AUTHOR]

This study aims to prepare an anti-washout grout using marine soft clay to stabilize the wind power pile foundations. The cement, hydroxypropyl-methyl cellulose ether (HPMC), and sodium silicate were chosen as the main materials to modify the marine soft clay, and the fluidity, bleeding rate, setting time, rheology, anti-washout characteristics, and compressive strength were investigated. The results showed that high cement content, HPMC, and sodium silicate decreased the workability of grout while enhancing the washout resistance. The addition of HPMC and sodium silicate would increase the yield stress and plastic viscosity of the grout. The sodium silicate content was the key factor influencing the early strength, while the cement content and HPMC affect the later strength. The microstructures including the morphology of C-S-H gels and the content of ettringite and calcium hydroxide significantly changed with the addition of sodium silicate, and Friedel's salt was observed through the microstructure analysis. This study can provide effective guidance for the utilization of marine soft clay, the preparation of anti-washout grout, and the control of pile foundation stability. [ABSTRACT FROM AUTHOR]

Microbial attacks rapidly degrade concrete structures in wastewater facilities, leading to brief service lifespans. Hence, producing concrete resistant to chemical and sulfuric acid corrosion is more cost-effective. In the present study, a total of six concrete mixtures incorporating 7.5% silica fumes (SF) and 10% natural zeolite (ZE) were immersed in 0.5% and 1% sulfuric acid solutions with a maximum pH threshold of 2 and 1, respectively, for 70 weeks. The specimens were regularly monitored for surface deterioration, mass change and crushing load change. To better understand the relationship between the pore structure of concrete mixtures and resistance to sulfuric acid, various durability tests such as rapid chloride penetration, water absorption, electrical resistivity and chloride diffusion coefficient were performed. Based on the results obtained, converting calcium hydroxide into calcium silicate hydrate gel through pozzolanic reactions and then refining the porosity of concrete with silica fumes (SF) and natural zeolite (ZE) was effective in enhancing the resistance of concrete to attack by sulfuric acid of relatively low concentration. As a result, using silica fumes (SF) and natural zeolite (ZE) is a lower-cost method for reducing corrosion rates to extend the service life of facilities, particularly in lower concentrations. [ABSTRACT FROM AUTHOR]

The sustainable microwave (MW) synthesis of hydroxyapatite (HAp) from decarbonized eggshells was investigated. Decarbonization of eggshells, as a natural source of calcium carbonate (CaCO3), was carried out in the current study at ambient conditions to reduce the footprint of CO2 emissions on our environment where either calcination or acidic direct treatments of eggshells produce CO2 emissions, which is a major cause for global warming. Eggshell decarbonization was carried out via the chemical reaction with sodium hydroxide (NaOH) alkaline solution in order to convert eggshell waste into calcium hydroxide (Ca(OH)2) and simultaneously store CO2 as a sodium carbonate (Na2CO3) by-product which is an essential material in many industrial sectors. The produced Ca(OH)2 was mixed with ammonium dihydrogen phosphate (NH4H2PO4) reagent at pH~11 before being subjected to MW irradiation at 2.45 GHz frequency for 5 min using 800 Watts to prepare HAp. The prepared Nano-HAp was characterized using X-ray diffraction (XRD) where the crystal size was ~28 nm using the Scherrer equation. The elongated rod-like nano-HAp crystals were characterized using scanning electron microscopy (SEM) equipped with dispersive energy X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). MW synthesis of decarbonized eggshells is considered as a sustainable and environmentally friendly route to produce promising bioceramics such as nano-HAp. Concurrently, decarbonization of eggshells offers the ability to store CO2 as a high value-added Na2CO3 material. [ABSTRACT FROM AUTHOR]