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The present case report describes the non-surgical treatment of alveolar inferior nerve paresthesia caused by the extrusion of calcium hydroxide as intracanal medicament. A 45-year-old female patient had a chief complaint of numbness and pain in the left lower lip region for 2 months. Radiographic examination revealed calcium hydroxide overflow into the mandibular canal. Irrigation of the root canal system with saline using a 27-gauge needle was done to remove as much calcium hydroxide as possible but proved ineffective in removing material from the outside tissues. Root canal treatment was completed in 1 week, and non-surgical paresthesia treatment with steroids and pregabalin was done for one month. In the 1-year follow-up control, the paresthesia had reduced significantly. In a 4-year follow-up visit, there was a complete resolution of paresthesia, and the radiographic analysis showed that calcium hydroxide was completely resorbed.

Objective: Some endodontic procedures require using intracanal medicament between treatment sessions. The effectiveness of these agents on dentin microhardness is crucial for deciding whether to use them or not. This study aimed to compare the effectiveness of three intracanal medicaments including Triphala, calcium hydroxide (Ca(OH)2) paste, and chlorhexidine (CHX) gel on the root dentin microhardness.Methods: Forty-eight single canal mature permanent teeth were selected. Mechanical preparation was done using RaCe rotary files. The samples were randomly allocated to four equal groups (n=12), according to the applied intracanal medicament. Group 1 received no medicament, whereas the root canals in groups 2, 3, and 4 were filled with Triphala, Ca(OH)2, and CHX, respectively. Specimens were stored for one week. Then, the roots were sectioned and the Vickers microhardness value was recorded at 0.5 mm from the pulp–dentin interface. Data were analyzed by one-way ANOVA and Tukey test and a P-value < 0.05 was considered statistically significant.Results: The mean microhardness values in the Triphala and calcium hydroxide groups were comparable to each other (P>0.05) and significantly lower compared to the control and CHX groups (P0.05).Conclusions: Triphala and Ca(OH)2 had similar effects on root dentin microhardness. Given the favorable characteristics of Triphala medicament, it can be considered a suitable alternative to Ca(OH)2 for intracanal application.

AbstractAim: Assessment of post-operative pain and quantification of bacterial endotoxins in adult patients suffering from necrotic pulp condition with chronic periapical periodontitis by using calcium hydroxide paste intracanal medication with 2% chlorhexidine gel, Calcium hydroxide paste intracanal medication only and with mechanical preparation without intracanal medications.Methods: Forty five patients with single rooted teeth suffering from necrotic pulp status were divided into 3 groups (n=15), the first group received mechanical preparation only , the second group received calcium hydroxide intracanal medication only, while the third group received mixture of calcium hydroxide and 2 % chlorhexidene gel intracanal medication. Numerical rating scale was used to assess the pain experience post operatively while chromogenic end point Limulus Amebocyte Lysate assay (LONZA) was used to quantify the amount of endotoxins. Results: Calcium hydroxide was superior in decreasing the postoperative pain at time interval 4 hours and 24 hours in comparison to the mixture of calcium hydroxide paste and 2 % chlorhexidene gel significantly, while the mixture was better to reduce the endotoxins with statistically insignificant value.Conclusion: Using one of the intracanal medications for 2 week time interval in necrotic teeth can help to allivate postoperative pain and reduce endotoxins.

Statement of the Problem: Endodontic efforts are focused on eliminating intracanal pathogens. Applying intracanal medicament for infected teeth is beneficial for achieving better antibacterial effects in endodontic treatments. Different intracanal medicaments should be assessed and compared for this purpose.Purpose: to assess the antibacterial efficacy of Citrullus colocynthis seed extract comparing to Ca(OH)2 on teeth contaminated with Enterococcus faecalis.Materials and Method: In this in vitro study, a novel strain of Enterococcus faecalis (Enterococcus spp. ATCC 19433) yielded from the root canal treated tooth with persistent apical periodontitis. The canals of 78 human single-rooted extracted teeth were contaminated with mentioned strain and treated with Citrullus colocynthis essential oil and Ca(OH)2 for 1, 7, and 14 days. To determine the chemical composition of the oils, gas chromatography-mass spectrometry (GC–MS) was applied. The percentage reduction from baseline c.f.u./mL values was estimated.Results: Oleic acid, benzoic acid, and gallic acid were the major contents of Citrullus colocynthis essential oil. The c.f.u./mL count decreased considerably as contact duration rose for both medicaments. After 7 days, a statistically significant difference was identified between the medicaments. Citrullus colocynthis showed higher antimicrobial efficacy. However, after 14 days, no substantial difference was found.Conclusion: Citrullus colocynthis essential oil, displayed great antimicrobial efficacy against Enterococcus faecalis higher than Ca(OH)2 over the first week contact period.

Abstract Background An innovative intracanal medication formulation was introduced in the current study to improve the calcium hydroxide (Ca(OH)2) therapeutic capability against resistant Enterococcus faecalis (E. faecalis) biofilm. This in-vitro study aimed to prepare, characterize, and evaluate the antibacterial efficiency of Ca(OH)2 loaded on Gum Arabic (GA) nanocarrier (Ca(OH)2-GA NPs) and to compare this efficiency with conventional Ca(OH)2, Ca(OH)2 nanoparticles (NPs), GA, and GA NPs. Materials and methods The prepared nanoparticle formulations for the tested medications were characterized using Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). 141 human mandibular premolars were selected, and their root canals were prepared. Twenty-one roots were then sectioned into 42 tooth slices. All prepared root canals (n = 120) and teeth slices (n = 42) were divided into six groups according to the intracanal medication used. E. faecalis was inoculated in the samples for 21 days to form biofilms, and then the corresponding medications were applied for 7 days. After medication application, the residual E. faecalis bacteria were assessed using CFU, Q-PCR, and SEM. Additionally, the effect of Ca(OH)2-GA NPs on E. faecalis biofilm genes (agg, ace, and efaA) was investigated using RT-PCR. Data were statistically analyzed at a 0.05 level of significance. Results The synthesis of NPs was confirmed using TEM. The results of the FTIR proved that the Ca(OH)2 was successfully encapsulated in the GA NPs. Ca(OH)2-GA NPs caused a significant reduction in the E. faecalis biofilm gene expression when compared to the control (p

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 wet dissolution process of lime is an effective approach for synthesizing calcium hydroxide. Process parameters and additives exert influence on the product particle. Among the process parameters, lime particle size, reaction temperature, and time have a significant impact on product particle size, followed by liquid‐solid ratio and stirring speed. The experiment proved that reaction time affects product particle size by affecting the crystal growth, while other process parameters affect the particle size by affecting the ion diffusion behavior. In terms of inorganic additives, Ca(OH)2 has minimal effect on product particle size; however, NaOH and CaCl2 can significantly enhance it with a greater dose leading to a larger increase. The experiment proved that Ca(OH)2, NaOH, and CaCl2 influence particle size through their impact on ion diffusion behavior. Regarding organic additives, soluble starch exhibits the greatest effect on product size followed by triethanolamine and polyvinylpyrrolidone K30. The experiment proved that soluble starch, triethanolamine, and polyvinylpyrrolidone K30 affect product particle size by influencing its crystallization position. Finally, an ultrafine slurry of calcium hydroxide was prepared using the lime wet digestion method based on the aforementioned research, with particle size distribution characterized by D10, D50, and D90 values of 0.303, 1.750, and 4.534 µm respectively. [ABSTRACT FROM AUTHOR]

In geopolymer mixes, the amount of shrinkage is (3–6 times) higher than the OPC. Excessive shrinkage can cause cracking, which is a threat to the durability of the concrete. To that end, a solution must be found to reduce it. Studies on the type and concentration of activators, type of base material and its properties, mixing proportions, applying different curing conditions and use of different additives are among the solutions investigated to decrease the drying shrinkage of geopolymers in previous research. In this study, after a comprehensive investigation, the effects of magnesium oxide, calcium hydroxide, sodium carbonate, and Portland cement additives as well as heat treatment and moist curing conditions were evaluated in geopolymer mortar containing slag activated with sodium hydroxide and sodium silicate. Finally, the performance of polypropylene fibers was examined as well. The effects of mentioned options on compressive strength were also investigated. The results indicate the different behaviors of additives on drying shrinkage and compressive strength depending on their type, substitution content, and age. Eventually, it seems that among the available alternatives, the most effective option is to use heat treatment with complete control of the heat rate. With this approach, not only the amount of drying shrinkage reduction will reach 66% but also the early compressive strength will be increased significantly. Although the use of magnesium oxide, sodium carbonate, and calcium hydroxide improved the compressive strength of the samples, relatively different results regarding shrinkage were observed in the use of these materials. Time-dependent behavior was also evident in their influence process. Polypropylene fibers also caused a slight decrease in compressive strength (less than 7.5%) probably due to the reduced compaction capacity of fresh mortar, but it was effective in controlling shrinkage in the short term. [ABSTRACT FROM AUTHOR]

The accumulation of alkali residue has led to significant contamination of soil, air, and water, posing a hazardous threat to the environment. To address this issue, a technology and method for producing alkali residue–based lightweight soil were proposed to facilitate the reuse of alkali residue, and the feasibility of this method was demonstrated. Compression tests, X-ray diffraction, X-ray fluorescence spectrometry, and scanning electron microscope (SEM) were conducted to investigate the strength characteristics and hardening mechanism of the material. The results indicate that the compressive strength of the alkali residue–based lightweight soil increases linearly with wet density, age, content of portland cement, and ground granulated blast slag. The optimal water–solid ratio was determined to be 0.6. Specimens with low and high strength exhibited plastic and brittle failures, respectively. The primary contributors to the material's compressive strength were identified as hydrated calcium silicate, ettringite, monosulfur calcium sulfoaluminate hydrate, hydrated calcium aluminate, and Friedel's salt. The 28-d compressive strength of the alkali residue–based lightweight soil, with a water–solid ratio of 0.6 and a wet density of 800.0 kg/m3 , was measured to be 1.17 MPa, meeting the requirements for most filling projects. [ABSTRACT FROM AUTHOR]

As the main hydration products, calcium-silicate-hydrate (C─ S─ H) and portlandite (CH) contribute significantly to the tensile strength of cementitious materials. However, the role of interface in the C─ S─ H/CH composites remains unexplored. This paper aims at elucidating the interfacial tensile properties of C─ S─ H/CH composites via molecular dynamics simulations with the ReaxFF forcefield. A method quantifying the thickness of the atomic-level interfacial transition zone in composites through potential energy analysis was proposed, with the value of 1.75–3.38 nm. Results showed that all models had damages at or near the interfaces. The tensile strength of composites relied highly upon material orientations. Elevated loading speed enhanced the tensile strength of composites, and their strain rate sensitivity was more significant than either C─ S─ H or CH. Failure mechanisms were revealed via chemical bond evolution. A nanoscopic tensile constitutive model was formulated based on Morse potential function. This research sheds light on the role of the interfacial area in two-phase composites at the atomic scale, which provides essential inputs for further multiscale studies. [ABSTRACT FROM AUTHOR]

Cement kiln dust (CKD) is a by-product of cement production, which has the shortcomings of low utilization and high-temperature activation. This study combined CKD and slag as precursors for preparing pastes through quicklime activation under ambient conditions. The effects of quicklime and CKD content on the workability (flowability and setting time), macro-mechanical properties, and micro-structure of the CKD-slag binders were analyzed. The experimental results showed that the rapid precipitation of Ca2+, Si4+, and Al3+ ions from the CKD provided more nucleation sites for the formation of calcium aluminosilicate hydrate (C-(A)-S-H) gel and enhanced the reactivity of the binder system under the influence of the activator (CaO). The specimens had the highest unconfined compressive strength (UCS) (24.6 MPa) after 28 days with 10% quicklime content and 60% CKD content; scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis showed that the Ca/Si ratio of the C-(A)-S-H gel was minimized, leading to a denser microstructure and better binding ability under this mixing proportion. Therefore, this study may provide novel binder materials with a high proportion of CKD under ambient conditions. [ABSTRACT FROM AUTHOR]

The low mechanical strength of a low-calcium fly ash (FA)–red mud (RM) geopolymer severely limits its application. Steel slag (SS) and Ca(OH)2 can provide calcium and alkali for the hydration process of a low-calcium FA-based geopolymer. In this study, SS was used to replace part of the RM, and Ca(OH)2 was introduced. The effects of SS and Ca(OH)2 on the properties of the FA-RM geopolymer were investigated. The experimental results show that SS promoted the matrix to generate more C(N)-A-S-H and C-S-H gels and optimized the pore structure, thereby improving the mechanical properties of the FA-based geopolymer. The addition of 4 wt.% Ca(OH)2 increased the hydration products of the FA-based geopolymer, the microstructure was denser, and the mechanical properties were significantly improved. The 28 d compressive strength of the FA-based ternary composite geopolymer prepared by replacing part of the RM with SS and adding Ca(OH)2 reached 30.6 MPa, which provided an experimental basis for the resource utilization of various bulk solid wastes. [ABSTRACT FROM AUTHOR]

Catalytic conversion of glucose to lactic acid is a green promising strategy for the effective utilization of biomass‐derived carbohydrates to generate valuable chemicals. The generation of lactic acid would also be distinguishing in different reaction atmospheres. In this work, we firstly investigated the decomposition of lactic acid and glucose transformation to lactic acid in H2. No obvious decomposition of lactic acid was observed in H2. The activity testing results showed that glucose could be completely converted over the selected hydroxides, while the formation of lactic acid was closely related to the alkalinity of hydroxide. The yield of lactic acid was remarkably obtained to be 87 % over Ca(OH)2 at 220 °C for 3 h. Stronger alkalinity of the catalyst would facilitate glucose isomerization to fructose, and then easily be transformed into dihydroxyacetone or glyceraldehyde intermediates through reverse aldol condensation, which is beneficial to the generation of lactic acid. [ABSTRACT FROM AUTHOR]

China's salt lakes contain an abundance of magnesium resources as high-magnesium brine, a by-product of potash fertiliser production is often discharged into salt lakes, causing environmental damage. Magnesium oxide from salt-lake brine can be used to produce magnesium oxychloride cement (MOC), but the calcium impurities present in salt lakes affect the properties of MOC. To investigate the effects of these impurities, magnesium oxide was produced by calcining a magnesium hydroxide precursor. By adding calcium hydroxide or calcium chloride, the incorporated calcium impurities were 0, 5 and 10% by mass of magnesium oxide. The compressive strength, heat of hydration, composition of the hydration product phases and the pore structure development of MOC samples were evaluated. It was found that Ca2+ ions increased the early strength and the rates of setting and hardening of the MOC. However, the presence of calcium impurities did not change the hydration phase composition. This is primarily because the Ca2+ ions promoted the participation of magnesium oxide in the hydration reaction and enhanced the early strength of the MOC. The findings of this study demonstrate the technical feasibility of utilising magnesium resources from salt lakes to prepare magnesium oxide and apply it in the production of MOC. [ABSTRACT FROM AUTHOR]

Ancient Chinese architecture drawing is a unique form of ancient Chinese art. Porcine blood hydrogels are distinctive ingredients used to prepare the composite material of the substrate layer for architecture drawing. This investigation was focused on the mechanism for porcine blood hydrogel formation. Based on the traditional Chinese recipe for the preparation of porcine blood-lime mortar, samples with different ratios of porcine blood and lime water were prepared, and the molecular-scale interactions between the lime water and proteins in the porcine blood were examined with FTIR spectroscopy, Raman spectroscopy, XRD, XPS, fluorescence spectroscopy, contact angle and rheology studies. The mechanical properties and morphological features of the samples were detected with a rheometer, universal material testing machine and SEM. The results indicated that an appropriate amount of lime water was required for gelation of the porcine blood. With the appropriate alkalinity, sufficient carboxyl groups on the fibrin chains were deprotonated, and coordination with Ca2+ ions formed enough cross-links for support networks within the structure of the porcine blood hydrogel. Complexation of deprotonated carboxyl groups on the fibrin chains with Ca2+ ions led to the formation of a hydrophobic surface due alterations of the fibrin conformation and increased the adhesive properties of the hydrogel. With the hydrogel used as an ingredient in the preparation of a substrate layer composite, it is suggested that the hydrophobic surface of the hydrogel facilitated mixing with hydrophobic tung oil during preparation of the composite material, and strong adhesion of the hydrogel increased the mechanical strength and crack resistance of the substrate layer. [ABSTRACT FROM AUTHOR]

Objectives: To perform a systematic review of animal studies that compared the histopathological characteristics between teeth with apical periodontitis after endodontic treatment in one or two visits. Materials and methods: This systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) – CRD42022340849. Studies were collected from PubMed/MEDLINE, LILACS, EMBASE, Livivo, SciELO, Web of Science, Scopus, and Cochrane Library and manual and gray literature searches. Animal studies that evaluated histological characteristics after endodontic treatment of teeth with apical periodontitis in one or two visits were included. Risk of bias analysis of the included studies was performed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. Data synthesis of the included studies with quantitative data was performed, and meta-analysis was conducted with the Comprehensive Meta-Analysis software, using the random effects model and odds ratio (OR). Results: Eighteen studies met the inclusion criteria (Kappa = 0.891). Meta-analyses indicated values in inflammatory infiltrate intensity with effect size of 5.5% (95% CI: 0.020–0.148; p < 0.001), periodontal ligament thickness: 25.6% (95% CI: 0.134–0.487; p < 0.001), dentin resorption: 13% (95% CI: 0.015–1.141; p = 0.066), cementum resorption: 7.1% (95% CI: 0.015–0.325; p = 0.001), bone resorption: 1.4% (95% CI: 0.002–0.130; p < 0.001), mineralized tissue resorption: 42.8% (95% CI: 0.110–1.671; p = 0.222), biological apical sealing: 13.1% (95% CI: 0.055–0.314; p < 0.001), and presence of microorganisms: 10.3% (95% CI: 0.014–0.747; p = 0.025). Conclusions: When considering animal studies, the two-visit endodontic treatment, using calcium hydroxide-based intracanal medication, resulted in better biological repair characteristics. Clinical relevance: A two-visit endodontic treatment with calcium hydroxide-based intracanal medication yields superior histopathological outcomes. [ABSTRACT FROM AUTHOR]

Dental biomaterials are commonly used in vital pulp therapy to protect dentin against degradation. However, the protection role of the ions diffusing in affected dentin in indirect pulp capping remains not fully understood due to the limitations of experimental techniques to validate it at the atomic scale. In this study, molecular dynamics (MD) is used for studying two bioactive materials, during mineral apatite formation and remineralization. LAMMPS code with DREIDING Force Field and Universal Force-Fields (UFF) simulated the behaviour of calcium hydroxide and mineral trioxide aggregate in the tooth structure in the oral environment. The comparison of the physical parameters provided by the simulation is discussed in detail to explore the possibilities of crystallization depending on potential energy, lattice constant, XRD pattern, atomic volume and radius of gyration. MD results show that the crystallization process occurs in both materials after about 10 ns, at 310 K and 1 bar. [ABSTRACT FROM AUTHOR]

Aim Methodology Results Conclusion 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.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.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.Calcium hydroxide‐loaded PLGA NPs dispersed in a thermosensitive gel may constitute a suitable alternative as an intracanal antibacterial medicament. [ABSTRACT FROM AUTHOR]

Stimulant betel quid (SBQ) containing Piper betle leaf (L), green unripe Areca catechu nut (AN) and the alkalizing agent, slaked lime, is an addictive, carcinogenic stimulant, with no pharmacotherapy, chewed by millions of people in the Asia/Pacific region. We compared the in vivo physiological profile of chewing (1) non‐stimulant P. betle leaf+AN (LAN), (2) SBQ utilizing slaked lime and (3) a novel SBQ utilizing Mg(OH)2, as an alkalizing agent, by measuring physiological parameters of intoxication and these were correlated with in vitro levels of alkaloids measured by UHPLC–MS/MS. Chewing LAN, which contains high levels of arecoline, had no stimulatory physiological effect. Chewing SBQ containing slaked lime or novel SBQ containing Mg(OH)2, induced equivalent stimulatory physiological responses. In vitro, slaked lime hydrolyzed muscarinic esters in LAN while Mg(OH)2 did not. The physiological stimulation induced by chewing both SBQ and the lack of physiology to chewing LAN can be explained by changes in lipid solubility of phytochemicals induced by mouth pH during chewing of basic SBQ or acidic LAN. Since antiquity people have added slaked lime to SBQ to enhance absorption of phyto‐chemicals across oral membranes to stimulate physiology. The same physiological changes can be induced by substituting slaked lime for less physically and chemically destructive bases. If attitudes regarding SBQ dependence can advance towards the more progressive attitudes already used to help smokers quit tobacco, modern chemistry has the potential to make chewing SBQ safer and quitting programs may become more accessible and efficacious. Chewing Piper betle leaf and green unripe Areca catechu nut (LAN), which contains high levels of arecoline, had no stimulatory physiological effect. Chewing stimulant betel quid (SBQ) containing LAN+slaked lime or SBQ containing LAN+Mg(OH)2, induced equivalent stimulatory physiological responses. Since antiquity people have added slaked lime to LAN to enhance absorption of phyto‐chemicals across oral membranes to stimulate physiology. The same physiological changes can be induced by substituting slaked lime for less physically and chemically destructive bases. [ABSTRACT FROM AUTHOR]

The ultrasonic pitch–catch method was used to study the hydration behaviour of Portland cement paste with sodium gluconate (SG) additive using a tailor-made piezoelectric transducer. X-ray diffraction analysis showed that the intensity of the diffraction peak of calcium hydroxide decreased with increasing SG content (CSG), especially for CSG > 0.10 wt%. The compressive strength of the hardening cement pastes decreased remarkably for the pastes with CSG > 0.05 wt%. Ultrasonic waveforms appeared after 2 h of hydration and the waveform amplitudes of cement pastes with SG contents of 0.15 wt% and 0.20 wt% were obviously larger than those of cement pastes with CSG = 0.05 wt% in the early hydration stage. The hydration process of the cement paste over 300 h was classified into three stages based on the head wave amplitude variation – the fluctuation period, the rapidly increasing period and the smoothly increasing period. The acoustic propagation time changed greatly with hydration before a hydration age of 48 h, indicating that the hydration and hardening process of the cement paste was intense in the first 48 h. The proposed ultrasonic monitoring method opens a new perspective for studying the hydration behaviour of SG-blended cement paste. [ABSTRACT FROM AUTHOR]

In present study, calcium hydroxide (Ca(OH)2) and calcium hydrogen phosphate dihydrate (DCPD) were subjected to a wet mechanochemical reaction for the first time to synthesize hydroxyapatite (HAp), as a noble-metal-free catalyst, towards efficient oxidative decomposition of volatile organic compounds (VOCs). The crystallinity, size and morphology, chemical composition and surface properties of the HAps synthesized using different mechanochemical conditions were investigated schematically. These properties were investigated using powder X-ray diffraction, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, and adsorption isotherms of acidic/basic gases. Moreover, the synthesis mechanism was clarified via detailed investigation of the elution dynamics of DCPD and Ca(OH)2 via the mechanochemical treatment. Consequently, the mechanism of mechanochemical reaction was found to involve a reaction between the DCPD activated by mechanochemical treatment and the Ca ions eluted from Ca(OH)2. In addition, the synthesized HAps were tested for oxidative decomposition of VOCs. The results suggest that the HAp synthesized via mechanochemical treatment exhibits enhanced catalytic performance compared to HAp prepared via conventional liquid-phase precipitation, and the catalytic activity significantly depends on the chemical structure determined by the mechanochemical condition. The details related to the synthesis mechanism and catalytic properties presented herein provide new insights in designing and developing novel catalyst materials. [ABSTRACT FROM AUTHOR]

Background/Aim: This study aimed at comparing the regenerative potential of injectable platelet‐rich fibrin (i‐PRF) (Group 1) and platelet‐rich plasma (Group 2) scaffolds. Materials and methods: Twenty‐three patients, aged from 9 to 24 years, having 24 immature traumatized necrotic maxillary anterior teeth, were enrolled. Teeth trauma was confirmed by patients' history. Preoperative three‐dimensional scans were done. In the first visit, canals were irrigated with 1.5% sodium hypochlorite then medicated with calcium hydroxide. After 2 weeks, patients were randomly assigned into one of the treatment groups (n = 12). The platelet concentrate was applied after centrifuging 10 mL of autologous venous blood with respect to the centrifugation protocol for each platelet concentrate. Patients were recalled at 6 and 12 months posttreatment, during which clinical and radiographic examinations and assessment of pulp sensitivity were done. Three‐dimensional scanning was done after 12 months. The increase in root length and decrease in root canal diameters were calculated at three canal levels. Statistical analysis was done using the paired t‐test and the independent t‐test. The significance level was set at p <.05. Results: There was no statistically significant difference between both groups regarding the increase in root length, decrease in coronal and middle canal diameters and the response to the electric pulp tester. Group (1) showed significantly greater decrease in apical canal diameter than Group (2) (p =.008). Conclusion: I‐PRF can be considered as a valid regenerative scaffold for clinical use and with regards to the easier preparation technique, it is more recommended than platelet‐rich plasma. [ABSTRACT FROM AUTHOR]

• Introduces in-depth key operating parameters and evaluates technical efficiency. • Dosage of urea, calcium hydrate and lye have relatively high improvement ratio. • Suggestions to promote the disposal facilities. Hazardous waste rotary kiln incineration, as the most effective and comprehensive technology to reduce and detoxify waste, generally faces problems such as low load rate and short continuous operating periods. However, there are few studies on the actual operation of such facilities and evaluation of their technical efficiency. Based on the 77-week time-series data of the case company, this study introduces in-depth key operating parameters and evaluates long-term technical efficiency through the data envelopment analysis (DEA) method. The results show that the continuous operating period of the rotary kiln incineration facility can reach more than half a year, with an average load rate of 91.7%. In the analysis of 9 input indicators, the amount of injected activated carbon could not be effectively evaluated due to the lack of relevant standards and online real-time monitoring of dioxins, which might become a weak link in the control of flue gas pollution. The average comprehensive technical efficiency of rotary kiln incineration facilities was 0.939, of which the average pure technical efficiency was 0.949 while the average scale efficiency was 0.989. With 33 of the 77 decision-making units being invalid, there is scope for improvement. The amount of incineration could be increased by 5.34%, and among the input variables, dosage of urea, calcium hydroxide and lye with a relatively high improvement ratio. Based on the results, targeted suggestions were proposed to advance the scientific and precise compatibility of hazardous waste, strengthen the control of dioxin emissions, and promote the intelligent control of the entire process. [ABSTRACT FROM AUTHOR]

To compensate for the defects of silica fume (SF), which aggravates drying shrinkage, and increase the strength and durability of cement mortar, it was modified using 1 wt% nanosilica (NS) or calcium sulfate whisker (CSW) compounded with 2 wt% SF. The strength, volume stability, and durability of the cement mortar were characterized using the compressive strength, drying shrinkage, and capillary water absorption. The physical composition and microstructure of the samples are discussed in detail based on thermogravimetry, mercury intrusion porosimetry, and scanning electron microscopy measurements. The combination of SF and NS increased the generation of C–S–H gels and reduced the total porosity, thus increasing the early strength of the cement mortar and decreasing the capillary water absorption. Notably, on combining SF and CSW, additional calcium aluminate hydrates (AFts) were generated, and the mesoporosity (10–50 nm) was reduced. The fibrous AFt phase increased the later strength of the cement mortar, and the presence of additional AFt increased the solid phase volume, which compensated for the drying shrinkage. [ABSTRACT FROM AUTHOR]

Natural indigo dye production produces indigo waste as a by-product. Our purpose of this study was to examine the effects of calcium hydroxide (Ca(OH)2), cellulase (CE), molasses (MO), and their combinations on the silage quality, in vitro degradability, and rumen fermentation parameters of indigo waste silage. A completely randomized design (CRD) was used for the experiment. Indigo waste was chopped and ensiled in a small-scale silo with no additive (control), Ca(OH)2, MO, CE, Ca(OH)2:MO, Ca(OH)2:CE, MO:CE, and MO:CE:Ca(OH)2. After 30 days of storage, the silages were tested for quality and chemical composition, as well as an in vitro fermentation. The ruminal fluid inoculum was collected from two beef cattle with a body weight (BW) of 200±10 kg, and the inoculum had been pre-heated before being transported to the laboratory. Silage with MO, CE, or their combination increased the amount of lactic acid (p < 0.01). The silage pH was lowest in MO:CE (4.5) and was highest in Ca(OH)2:CE (10.6) in indigo waste (p < 0.01). In comparison to the control (19.5% CP), the CP content of all additives increased by 20.7% to 21.5% (p = 0.02). The addition of Ca(OH)2:MO and Ca(OH)2:CE resulted in a reduction of NDF content by 60.7% and 59.4%, respectively, in comparison to the control group (72.4%) (p < 0.01). Silage with additives had no effect on the cumulative gas production or gas kinetics, except that the constant rate of gas production for the insoluble fraction (c) was higher in MO (p = 0.03). In vitro dry matter degradability (IVDMD) was higher in CE and MO and highest in MO:CE-treated silage (p < 0.01). The in vitro organic matter degradability (IVOMD) increased in Ca(OH)2:MO compared with the control (p = 0.03). The additives alone or in their two combinations in silage reduced the ruminal ammonia-nitrogen (NH3-N) concentration (28.0 to 31.5 mg/dL) when compared to the control (32.7 mg/dL) (p < 0.01). In addition, the highest total volatile fatty acid (VFA) level was found in the silage of the MO (92.9 mmol/L) compared with the control (71.3 mmol/l) (p < 0.01). The proportion of propionic acid and butyric acid increased (p < 0.01) whereas acetic acid decreased (p < 0.01) in the rumen of silage with MO and CE. In summary, the addition of MO and CE has the potential to be used in the silage of indigo waste.

Abstract Background Calcium hydroxide [Ca(OH)2] is widely accepted as a biocompatible interappointment intracanal medicament. This study aimed to analyze the efficacy of Ca(OH)2 placement into the C-shaped canal system of mandibular second molars using the syringe method with and without lentulo spiral utilizing micro-computed tomography (micro-CT). Methods Twenty-four extracted mandibular second molars were instrumented and classified into C-shaped floors (n = 12) and non-C-shaped floors (n = 12). Both groups were placed with Ca(OH)2 using the syringe system, then all teeth were scanned and cleaned, and placed with Ca(OH)2 again but with the syringe system followed by lentulo spiral and rescanned. The specimens were scanned using micro-CT to analyze the volume, volume percentage, uncontacted surface area, and uncontacted surface area percentage of Ca(OH)2 with the two delivery methods in the entire canal and at the apical 4 mm of the canal. Mann-Whitney test and Wilcoxon signed-rank test were used to determine the statistical differences among the groups. Results Syringe administration used in conjunction with lentulo spiral presented lower uncontacted surface area, a lower percentage of uncontacted surface area, larger volume, and a higher percentage of volume than syringe without lentulo spiral (P 0.05) in the Ca(OH)2 uncontacted surface area, volume, and percentages at different regions of canals and among different delivery techniques groups. Conclusions The lentulo spiral and syringe technique combination can increase the volume and contacted surface area of Ca(OH)2 in the C-shaped canal system of mandibular second molars.

Abstract Objectives Different materials have been used for capping the pulp after exposure during caries removal in permanent teeth. The purpose of this study was to collate and analyze all pertinent evidence from randomized controlled trials (RCTs) on different materials used in patients undergoing pulpotomy or direct pulp capping in carious teeth. Materials and Methods Trials comparing two or more capping agents used for direct pulp capping (DPC) or pulpotomy were considered eligible. An electronic search of four databases and two clinical trial registries was carried out up to February 28, 2021 using a search strategy properly adapted to the PICO framework. Screening, data extraction, and risk of bias (RoB) assessment of primary studies were performed in duplicate and independently. The primary outcome was clinical and radiological success; secondary outcomes included continued root formation, tooth discoloration, and dentin bridge formation. Results 21 RCTs were included in the study. The RoB assessment indicated a moderate risk among the studies. Due to significant clinical and statistical heterogeneity among the studies, performing network meta‐analysis (NMA) was not possible. An ad hoc subgroup analysis revealed strong evidence of a higher success of DPC with Mineral Trioxide Aggregate (MTA) compared to calcium hydroxide (CH) (odds ratio [OR] = 3.10, 95% confidence interval [CI]: 1.66−5.79). MTA performed better than CH in pulp capping (both DPC and pulpotomy) of mature compared to immature teeth (OR = 3.34, 95% CI: 1.81−6.17). The GRADE assessment revealed moderate strength of evidence for DPC and mature teeth, and low to very low strength of evidence for the remaining subgroups. Conclusions Considerable clinical and statistical heterogeneity among the trials did not allow NMA. The ad hoc subgroup analysis indicated that the clinical and radiographic success of MTA was higher than that of CH but only in mature teeth and DPC cases where the strength of evidence was moderate. PROSPERO Registration: number CRD42020127239.

Abstract The composition-processing-structure-properties relationship of Na2O-Al2O3-SiO2-based geopolymers containing calcium sources is critical for the design of enhanced ceramic binders. This work evaluated the addition of 1-6 wt% of calcium hydroxide (CH) to a metakaolin-based geopolymer (prepared with NaOH 12 M and colloidal silica suspension) and how it affected the performance of the prepared samples after thermal treatments up to 1000 °C. The setting time, mechanical strength, porosity, density, permanent linear change, and phase and bond type evolution of the specimens with temperature were analyzed. The incorporation of 3 or 6 wt% of CH into the designed composition led to a fast hardening of the mixtures (1.7 h), resulting in geopolymers with high green mechanical strength (18.9 to 23.9 MPa). Nepheline and albite generation in the samples containing 6 wt% of CH resulted in a ceramic with improved cold crushing strength (45.2 MPa) and lower linear shrinkage (-10.5%) when compared to the calcium-free composition.

The aim of direct pulp capping (DPC) is to promote pulp healing and mineralized tissue barrier formation by placing a dental biomaterial directly over the exposed pulp. Successful application of this approach avoids the need for further and more extensive treatment. In order to ensure a complete pulp healing with the placement of restorative materials, a mineralized tissue barrier must form to protect the pulp from microbial invasion. The formation of mineralized tissue barrier can only be induced when there is a significant reduction in pulp inflammation and infection. Consequently, promoting the healing of pulp inflammation may provide a favorable therapeutic opportunity to maintain the sustainability of DPC treatment. Mineralized tissue formation was observed as the favorable reaction of exposed pulp tissue against a variety of dental biomaterials utilized for DPC. This observation reveals an intrinsic capacity of pulp tissue for healing. Therefore, this review focuses on the DPC and its healing procedure as well as the materials used for DPC treatment and their mechanisms of action to promote pulpal healing. In addition, the factors that can affect the healing process of DPC, clinical considerations and future perspective has been described.

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]

Abstract This study investigated the effect of dolomitic lime incorporation on the microstructure and mechanical properties of metakaolin-based geopolymers activated by alkaline solution. Five geopolymer mixtures were prepared with the addition of 0.0%, 2.5%, 5.0%, 7.5%, and 10.0% dolomitic lime. The microstructure of the geopolymers was evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction analyses (XRD). The compressive strength of the mixtures ranged between 53.2 and 63.0 MPa after 28 days of ambient curing. SEM/EDS analyses showed that the main phases formed were the N-A-S-H gel together with the C-A-S-H and N-M-A-S-H gels in the mixtures with dolomitic lime. In summary, the results showed that the incorporation of dolomitic lime can significantly improve the microstructure and properties of geopolymers.

Objective: To evaluate the effectiveness of ethanol compared to citric acid in the removal of oil-based calcium hydroxide from the apical third of the root canal system using passive ultrasonic irrigation. Method: The in vitro study was conducted from September to October 2021 at the dental clinics of the Aga Khan University Hospital, Karachi, and comprised single-rooted teeth that were selected from institutional bank of extracted teeth. They were randomly divided into group A having 70% ethanol + passive ultrasonic irrigation, group B 10% citric acid + passive ultrasonic irrigation, group C positive controls and group D negative controls. The specimens were sectioned at 1mm and 3mm from the apex and examined under a dental operating microscope. A single examiner scored the specimens on two different occasions. Data was analysed using SPSS 25. Results: Of the 90 teeth, there were 40(44.4%) in each of the 2 experimental groups and 5(5.5%) in each of the 2 control groups. At 3mm apical sections, ethanol was significantly more effective in the removal of oil-based calcium hydroxide (p=0.01). However, at 1mm from the apex, there was no significant difference between the experimental groups (p=0.064). Intragroup comparison showed that for groups A and B, residual medicament at 1mm sections was significantly greater than at 3mm sections (p

This study aimed to compare the syringe-needle irrigation (SNI), passive ultrasonic irrigation (PUI), EDDY, and shock wave–enhanced emission photoacoustic streaming (SWEEPS) techniques regarding calcium hydroxide and double antibiotic paste removal from the root canal in regenerative endodontic treatments. Eighty single-rooted human teeth were decoronated and enlarged up to #100 to stimulate the immature tooth model. Root canals were irrigated with 1.5% sodium hypochlorite followed by saline solution according to the regenerative endodontic treatment protocol. Dressed teeth were divided into 2 main groups regarding the used intracanal medicaments. Calcium hydroxide and double antibiotic paste were introduced to the canals, and teeth were stored for 3 weeks. Each medicament group was divided into 4 subgroups according to the activation techniques. Medicaments were removed using a 17% EDTA solution. Teeth were split longitudinally into two parts. The remaining medicaments were evaluated under a stereo microscope with a scoring system. Data were analyzed with the Kruskal-Wallis and Mann-Whitney U tests. Regardless of the used irrigation activation systems, there was no statistically significant difference between the removal of the CH and DAP from the root canal (P>0.05). While SWEEPS had the highest ability regarding the removal of intracanal medicaments, syringe-needle irrigation had the lowest (P<0.05). There was no statistically significant difference between PUI and EDDY (P>0.05). Complete removal of intracanal medicaments could not be achieved with any techniques. SWEEPS technology was more effective in removing intracanal medicaments in regenerative endodontic treatments compared to the sonic and ultrasonic irrigation activation systems. [ABSTRACT FROM AUTHOR]

Objective: To investigate the clinical efficacy of three materials, mineral trioxide agglomerate（MTA), i Root BP Plus（i RooT), and calcium hydroxide（Ca(OH)2), in the live pulpotomy of young permanent teeth. Methods: Sixty patients（60 affected teeth）requiring vivipectomy of young permanent teeth were randomly divided into three groups according to the materials used: the MTA group, the i RooT group and the Ca(OH)2 group, with 20 patients（20 affected teeth） in each group. The success rate of the procedure, the incidence of dentin bridge formation and tooth discoloration, root canal wall thickness, tooth function and aesthetics, and serum matrix metalloproteinase-3（MMP-3） and interleukin-8（IL-8） levels were compared between the three groups at 3 and 6 months after surgery. Results:（1） The clinical treatment success rate was different among the three groups at 6 months postoperatively only（P＜0. 05); （2） The postoperative dentin bridge formation rate was lower in the Ca(OH)2 group than in the other two groups（P＜0. 05), while the incidence of tooth discoloration was lower in the MTA group（P＜0. 05） and higher than in the i RooT group（P＜0. 05). （3） The root canal wall thickness increased in all three groups after treatment compared with that before treatment, and the increase in root canal wall thickness in the Ca(OH)2 group was lower than that in the MTA and i RooT groups after treatment（P＜0. 05). （4） The dental comfort function, fixed function and masticatory function scores were significantly lower in the Ca(OH)2 group than in the MTA and i RooT groups at 6 months postoperatively（P＜0. 05), while the dental esthetics scores were lower in the i RooT group（P＜0. 05） and higher than in the MTA group（P＜0. 05). （5）Serum MMP-3 and IL-8 were lower in all three groups 6 months after surgery than before surgery（P＜0. 05), and the serum MMP-3 and IL-8 levels were higher in the MTA group than in the i RooT group（P＜0. 05） and lower in the CaOH group（P＜0. 05). Conclusion: Both i Root BP Plus and MTA materials have high long-term success rates for vivisection of young permanent teeth, but the MTA material has a high rate of long-term tooth discoloration and thus affects the aesthetics of the teeth. [ABSTRACT FROM AUTHOR]

Objective: determine which of these intracanal medications (calcium hydroxide, chitosan, and calcium hydroxide+chitosan), shows more antibacterial effect on the sensitivity of Enterococcus faecalis bacterium. Methodology: an in vitro study was carried out using the antimicrobial susceptibility technique applying the microdilution method in order to establish whether a concentration of the compounds was in three groups: Cluster 1: calcium hydroxide. Cluster 2: Chitosan. Cluster 3: calcium hydroxide + chitosan has antibacterial activity against the Enterococcus faecalis bacterium and to support this test, the antibiogram technique was performed by measuring inhibition halos to determine the sensitivity of E. faecalis to intracanal medications calcium hydroxide and chitosan. Results: there are statistically significant differences in the intracanal medications of calcium hydroxide, chitosan, and calcium hydroxide+chitosan against the bacterium Enterococcus faecalis, showing better results when chitosan is used alone, in the colony-forming unit and in the antibiogram technique for inhibition halos showed better results. Limitations: due to the shortage of Ketamine in hospital units, it is difficult to replicate the study in larger samples. Value: a similar study has not been carried out at the Escuela Militar de Graduados de Sanidad. Conclusions: chitosan is effective against E. faecalis, it can significantly reduce the number of bacteria at a low dilution of 100 mg/ml, therefore we can conclude that chitosan is a promising candidate for an alternative biocompatible antibacterial agent and can be used as a intracanal medication in root canal treatments. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cerium ions promote osteoclastogenesis and activate bone metabolism, while cerium oxide nanoparticles exhibit potent anti-inflammatory properties, making them promising for biomedical applications. OBJECTIVE: The purpose of this study was to develop and evaluate a synthesis method for sustained-release cerium-ion bioceramics containing apatite. Substituted apatite was found to be an effective biomaterial. METHODS: Cerium-containing chlorapatite was synthesized using a mechanochemical method employing dicalcium phosphate, cerium chloride heptahydrate, and calcium hydroxide as raw materials. The synthesized samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. RESULTS: Cerium chlorapatite was successfully synthesized in the 10.1% and 20.1% samples. However, at Ce concentrations higher than 30.2%, the samples consisted of three or more phases, indicating the instability of a single phase. CONCLUSION: The method used in this study was found to be more efficient and cost-effective than the precipitation method for producing substituted apatite and calcium phosphate-based biomaterials. This research contributes to the development of sustained-release cerium-ion bioceramics with potential applications in the field of biomedicine. [ABSTRACT FROM AUTHOR]

Carbon dioxide and kimchi odor compounds, formed during fermentation, negatively affect the long‐distance distribution of commercial kimchi. To address these issues, in this study, we modified different porous media (activated carbon, bleaching earth, diatomite, and zeolite) using sodium bicarbonate and silver (Ag) ions. Functional sheets were prepared using linear low‐density polyethylene, calcium hydroxide, a porous medium, and a blowing agent. Various prepared porous media and sheets were effective in removing acetic acid, sulfur compounds (allyl methyl sulfide, dimethyl disulfide, allyl methyl disulfide, and diallyl disulfide), and carbon dioxide. Porous media with micropores exhibited a sulfur compound removal efficiency of 43.5%–99.4%, while no effect was observed on acetic acid removal. However, porous media with mesopores showed an acetic acid removal efficiency of 42.3%–90.7%, with no reduction in sulfur compounds removal. The impregnation of porous materials with sodium bicarbonate significantly (p < 0.05) enhanced the acetic acid removal activity. Ag modification improved the sulfur compound removal of the mesoporous bleaching earth and diatomite statistically (p < 0.05). Additionally, the incorporation of sodium bicarbonate‐impregnated mesoporous media significantly improved carbon dioxide removal, reducing concentrations from 25.97% to 14.27% with respect to the control group. Our functional food packaging materials can solve the current issues in kimchi distribution by removing carbon dioxide and kimchi odor without affecting its quality. Practical Application: Food active packaging materials containing calcium hydroxide and modified porous medium are effective in removing carbon dioxide and kimchi odor (acetic acid and sulfur compounds). The removal of carbon dioxide and kimchi odor, which adversely affect the distribution and sale of commercial kimchi, can help solve the current issues with kimchi distribution without affecting its quality. [ABSTRACT FROM AUTHOR]

Raw earth construction (RE) is an interesting alternative approach for reducing the use of conventional construction materials. The aim of this study is the stabilization of RE by a new organic binder manufactured based on algae. The stabilization is performed on the mortar scale as well as evaluated by conducting mechanical and thermal tests. Samples of mortar were manufactured based on local soil and Sargassum muticum type algae. The incorporation weight rates of algae are 0 (reference sample), 2, 4, 6, and 8 wt.%. Results showed that the compressive and bending strengths of algae mortar were improved by 77 and 70%, respectively. In addition, it was noticed that samples with 0.63 mm maximum grain size algae binder provide higher strengths in comparison with 0.80 mm maximum grain size algae binder. It was found also that 2 wt.% of incorporated algae provide similar mechanical resistance to 15 wt.% of slaked lime. The thermal investigation of samples showed three peaks: two endothermic peaks at 100 and 800 °C, which can be respectively attributed to the desorption of H2O and CO2 due to the decomposition of calcite; the third exothermic peak at 500 °C is attributed to the decomposition of the macromolecules of the algae. [ABSTRACT FROM AUTHOR]

Annually tons of waste engine oil is wasted or dumped in environmentally unfriendly ways. Asphalt binder has been modified with waste engine oil previously and showed, lower consistency, lower moisture damage resistance at higher dosages, and impaired high-temperature performance. In the current study, three different additives were added to solve these issues associated with waste engine oil-modified bitumen. Elvaloy, polyphosphoric acid (PPA), and hydrated lime (H-L) were used as polymer, chemical, and filler-type additives. Waste engine oil-modified bitumen combined with all three types of additives was evaluated using conventional viscosity, moisture susceptibility, dynamic mechanical, and chemical testing. Results showed that waste engine oil inclusion decreased the consistency of binder, reduced viscosity, and impaired high-temperature performance. Elvaloy's addition to waste engine oil-modified bitumen made it less sensitive to temperature changes, increased the performance grade, improved the stiffness, and enhanced the resistance against rutting and moisture-induced damages. Polyphosphoric acid addition refined the consistency of binder modified with waste engine oil. It drastically increased the complex modulus values and decreased phase angle values by stiffening the binder. PPA enhanced the moisture susceptibility of asphalt and improved its high-temperature performance. Hydrated lime improved moisture resistance and bonding strength but showed less effectiveness in improving high-temperature performance at lower dosages. The results conclude that binder modification with waste engine oil can be effective with other additives like polyphosphoric acid, Elvaloy, and hydrated lime. [ABSTRACT FROM AUTHOR]

Due to the presence of free lime (FL) in slag and its lack of reaction with concrete components, concrete containing slag reduces strength. Pozzolanic Portland cement (PPC) in the presence of moisture and normal heat during chemical reactions with lime (calcium hydroxide) generates stable calcium silicates that have adhesion properties. By using PPC instead of Portland cement type I in roller compacted concrete (RCC) containing basic oxygen furnace slag (BOFS), it is possible to determine the mechanical properties of RCC due to the reaction between the FL in BOFS and PPC. Therefore, this study aims to investigate the effect of PPC on the mechanical properties of RCC containing BOFS. For this purpose, specimens are made with various cement content values (225-400 kg/m3), various BOFS content values (0-50%) and with the optimum moisture. The properties examined in this paper are compressive strength, indirect tensile strength, and static modulus of elasticity tests. The results show that the use of PPC is effective in compensating the negative impact of using BOFS and providing the minimum specified mechanical properties. Also, the proportion of consumption of PPC with BOFS value is determined for the possibility of maximum reaction between FL and pozzolan in cement. [ABSTRACT FROM AUTHOR]

The performance of Cold mix asphalt (CMA) is influenced by the curing temperature. This study investigated the strength formation for CMA containing hydrated lime (HL) and silica fume (SF) as filler (0%–100% by weight of filler portion) and treated with 1% cement to compare with Hot mix asphalt (HMA). Moreover, three accelerated curing regimes (38°C, 40°C & 60°C) and ambient temperature (28–32°C) curing for three days are proposed to improve performance of the mixtures. The results have indicated a significant improvement in laboratory parameters in terms of stability and fatigue life for higher temperature (40°C and 60°C) cured mixes. Although the tensile strength of CMA is lower than HMA, despite that it shows improvement up to 68.19% at 60°C. The rutting depth of cement-treated CMA (CMA-CT) containing 50% HL and 50% SF was 58.63% lower than HMA when the samples were cured at 60°C. The accelerated curing enhances the stiffness of CMA mixes up to 344.82%. Overall, the research suggests that the use of 50% SF and 50% HL filler might be appropriate for both the CMA and CMA-CT mixes in terms of effective mixture properties. And the accelerated curing can mitigate the inferior performance issues related to CMA. [ABSTRACT FROM AUTHOR]

The present study aimed to understand the impact of inert-active filler combinations on cracking and resistance of asphalt mastic using work of fracture approach. A control grade asphalt binder (VG-30) and three fillers (inert: basalt (B); active: hydrated lime (HL) Nano hydrated lime (NHL)) were considered. The HL and NHL were added from 0% to 20% at 5% increment rate by weight of binder. The dosages of B were adjusted with respect to specific filler to binder ratios (0.6 to 1.2). The study focused on the influence of NHL on cracking resistance of mastic by means of ductile and fracture behaviour, evaluated using double edge notched tension test (DENT) at intermediate temperature condition. Findings indicated a beneficial impact in improving the cracking and fracture resistance of mastic due to reduction in the size of HL (NHL). The results signify that both HL and NHL can enhance the resistance to withstand ductile failure and fracture. Also, mastic prepared with B-NHL can be less susceptible to fracture over B-HL and hence, possessed improved ductile properties. Consequently, a lower dosage of NHL found to be superior over a higher dosage of HL in improving the cracking and fracture resistance of asphalt mastic. [ABSTRACT FROM AUTHOR]

Water insoluble calcium hydroxide Ca(OH)2 or calcium carbonate CaCO3 react with aqueous solution of (1-hydroxyethylidene)diphosphonic acid and nitrilotrimethylenephosphonic acid to form poorly soluble calcium (1-hydroxyethylidene)diphosphonate trihydrate and calcium nitrilotrimethylenephosphonate trihydrate, respectively. The reaction of calcium chloride CaCl2 with the disodium salt of ethylenediaminetetraacetic acid afforded poorly soluble calcium ethylenediaminetetraacetate hexahydrate. The reaction of suspensions of complexes of (1-hydroxyethylidene)calcium diphosphonate trihydrate, calcium ethylenediaminetetetraacetate hexahydrate and calcium nitrilotrimethylenephosphonate trihydrate with 2-aminoethanol led to the formation of water-soluble (1-hydroxyethylidene)bis(2-aminoethanol)calcium diphosphonate, tris(2-aminoethanol)calcium nitrilotrimethylenephosphonate, and bis(2-aminoethanol)calcium ethylenediaminetetraacetate, respectively. The molecular structure of calcium ethylenediaminetetraacetate hexahydrate was characterized by single-crystal X-ray diffraction method. [ABSTRACT FROM AUTHOR]