Artículos de revistas: "Diffusion hydroxide"

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Mizrachi, S. y M. Hunger. "Proton diffusion in calcium hydroxide". Journal of Physics: Condensed Matter 2, n.º 6 (12 de febrero de 1990): 1499–507. http://dx.doi.org/10.1088/0953-8984/2/6/009.

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Zelovich, Tamar y Mark E. Tuckerman. "OH− and H3O+ Diffusion in Model AEMs and PEMs at Low Hydration: Insights from Ab Initio Molecular Dynamics". Membranes 11, n.º 5 (12 de mayo de 2021): 355. http://dx.doi.org/10.3390/membranes11050355.

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Fuel cell-based anion-exchange membranes (AEMs) and proton exchange membranes (PEMs) are considered to have great potential as cost-effective, clean energy conversion devices. However, a fundamental atomistic understanding of the hydroxide and hydronium diffusion mechanisms in the AEM and PEM environment is an ongoing challenge. In this work, we aim to identify the fundamental atomistic steps governing hydroxide and hydronium transport phenomena. The motivation of this work lies in the fact that elucidating the key design differences between the hydroxide and hydronium diffusion mechanisms will play an important role in the discovery and determination of key design principles for the synthesis of new membrane materials with high ion conductivity for use in emerging fuel cell technologies. To this end, ab initio molecular dynamics simulations are presented to explore hydroxide and hydronium ion solvation complexes and diffusion mechanisms in the model AEM and PEM systems at low hydration in confined environments. We find that hydroxide diffusion in AEMs is mostly vehicular, while hydronium diffusion in model PEMs is structural. Furthermore, we find that the region between each pair of cations in AEMs creates a bottleneck for hydroxide diffusion, leading to a suppression of diffusivity, while the anions in PEMs become active participants in the hydronium diffusion, suggesting that the presence of the anions in model PEMs could potentially promote hydronium diffusion.

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Piana, Tatiana Dantas, Maria de Fátima Malvar Gesteira, Erica Dos Santos Carvalho, Josilene Borges Torres Lima Matos, Monica Franca, Leandro Miranda de Araújo y Silvio José Albergaria Da Silva. "Evaluation of the antimicrobial effect of calcium hydroxide combined to different vehicles". Revista Odonto Ciência 31, n.º 2 (26 de diciembre de 2016): 89. http://dx.doi.org/10.15448/1980-6532.2016.2.21522.

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Objective: To evaluate the potentiating effect of different substances in antimicrobial action of calcium hydroxide.Methods: The agar diffusion method, was used with well technique, to analyze seven substances associated to calcium hydroxide to make some pastes, they are: chlorexidine, saline, anesthetic, malvatricin, propolis, hypochlorite, paramonochlorophenol.Results: The pastes with malvatricin and paramonochlorophenol presented greater inhibition zones against Enterococcus faecalis.Conclusion: There was potentialization in antimicrobial effect of calcium hydroxide when associated to paramonochlorophenol and to malvatricin especially against Enterococcus faecalis. Low increase of the antimicrobial capacity was observed when using chlorexidine as vehicle to calcium hydroxine paste.

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Zelovich, Tamar y Mark E. Tuckerman. "(Invited) First-Principles Molecular Dynamics Investigations of Proton and Hydroxide Transport in Model Anion-Exchange- and Proton-Exchange Membranes in Nanoconfined, Low-Hydration Environments". ECS Meeting Abstracts MA2023-01, n.º 45 (28 de agosto de 2023): 2473. http://dx.doi.org/10.1149/ma2023-01452473mtgabs.

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Fuel cell-based anion-exchange membranes (AEMs) and proton exchange membranes (PEMs) have considerable potential as cost-effective, clean energy conversion devices. However, a fundamental atomistic understanding of the hydroxide and hydronium diffusion mechanisms in AEM and PEM environments is an ongoing challenge. In recent years, nano-confined structures have been exploited in the study of cost-effective and reliable polymer architectures for electrochemical devices. In this study, first-principles molecular dynamics simulations are employed to investigate the influence of the water distribution, temperature, internal geometry, cation chemistry, and presence of carbon dioxide on the diffusion rate of protons and hydroxide ions in nanoconfined geometries that serve as mimics of PEM and AEM environments and to reveal key design principles1-8. The simulations indicate that the water distribution is a determinative factor in the diffusion process, which is also arrested when carbon dioxide is present. Moreover, it is found that hydroxide diffusion in AEMs is largely vehicular or a combination of vehicular and structural while proton diffusion in PEMs is largely structural. Pairs of cations in AEMs create bottlenecks for hydroxide diffusion while the anion groups in PEMs become active participants in proton diffusion. It is found that the temperature dependence of hydroxide diffusion in AEMs is non-monotonic, exhibiting a “kink” over a particular temperature range at which dD OH ─/dT < 0, a finding that is confirmed experimentally. The presence of carbon dioxide is found to suppress hydroxide diffusion, also in agreement with experiment. Looking forward, we investigate the influence of the solvent chemistry on proton transport and propose new nanoconfined environments with the potential to enhance proton transport rates considerably using these liquids. References: Ab initio molecular dynamics study of hydroxide diffusion mechanisms in nanoconfined structural mimics of anion exchange membranes.” T. Zelovich, Z. Long, M. A. Hickner, S. J. Paddison, C. Bae, and M. E. Tuckerman J. Phys. Chem. C 123, 4683 (2019). “Hydroxide ion diffusion in anion-exchange membranes at low hydration: Insights from ab initio molecular dynamics.” T. Zelovich, L. Vogt-Maranto, M. A. Hickner, S. J. Paddison, C. Bae, D. R. Dekel, and M. E. Tuckerman Chem. Mater. 31, 5778 (2019). “Water layering affects hydroxide diffusion in functionalized nanoconfined environments.” T. Zelovich and M. E. Tuckerman J. Phys. Chem. Lett. 11, 5087 (2020). “Hydronium ion in model proton exchange membranes at low hydration: Insights from ab initio molecular dynamics.” T. Zelovich, K. I. Winey, M. E. Tuckerman J. Mat. Chem. A 9, 2448 (2021). “Non-monotonic temperature dependence of hydroxide diffusion in anion exchange membranes.” T. Zelovich, L. Vogt-Maranto, C. Simari, I. Nicotera, M. A. Hickner, S. J. Paddison, C. Bae, M. E. Tuckerman Chemistry of Materials 34 2133 (2022). “Controlling hydronium diffusivity in model proton exchange membranes.” T. Zelovich, M. E. Tuckerman J. Phys. Chem. Lett. 13, 2245 (2022). “The impact of carbonation on hydoxide diffusion in nanoconfined anion exchange membranes.” Zelovich, C. Simari, I. Nicotera, D. R. Dekel, M. E. Tuckerman J. Mat. Chem. A (2022). “Functional Groups in Anion Exchange Membranes: Insights From Ab Initio Molecular Dynamics.” T. Zelovich, D. Dekel, M. E. Tuckerman J. Membrane Sci. (submitted) Figure 1

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Leaist, Derek G. y Betty Wiens. "Interdiffusion of acids and bases•HCl and NaOH in aqueous solution". Canadian Journal of Chemistry 64, n.º 5 (1 de mayo de 1986): 1007–11. http://dx.doi.org/10.1139/v86-169.

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Stokes magnetically stirred diaphragm cells have been used to measure interdiffusion of hydrochloric acid and sodium hydroxide in aqueous solution at 25 °C. Expressions are developed to estimate ternary diffusion coefficients for these mixtures. The analysis reveals sharp discontinuities between the diffusion properties of HCl-rich and NaOH-rich mixtures. Although the diffusion coefficients are sensitive to concentration, accurate analytic approximations for rates of interdiffusion can be obtained by averaging coefficients along the diffusion path. When HCl and NaOH interdiffuse, proton-coupled and hydroxide-coupled diffusion operating simultaneously on opposite sides of the diffusion boundary lead to rapid diffusion of inert Na+ and Cl− species.

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Jacobson, Aaron J., Gregory D. Smith, Rallming Yang y Sujit Banerjee. "Diffusion of sulfide into Southern pine (Pinus taeda L.) and sweetgum (Liquidambar styraciflua L.) particles and chips". Holzforschung 60, n.º 5 (1 de agosto de 2006): 498–502. http://dx.doi.org/10.1515/hf.2006.082.

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Abstract Sulfide diffusion into wood has a rapid reversible component and a much slower irreversible component. During the initial reversible phase, sulfide is unable to diffuse into parts of the wood structure, probably because of charge exclusion. The diffusion of hydroxide and sulfide into saturated wood was imaged by immersing chips in white liquor, splitting them open and then imaging the hydroxide and sulfide profiles. Sulfide moves into the interior of the chip at a faster rate than hydroxide does because it is prevented from entering some of the pores and must move deeper into the chip to access dilution water.

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Leaist, Derek G. "Moments analysis of restricted ternary diffusion: sodium sulfite + sodium hydroxide + water". Canadian Journal of Chemistry 63, n.º 11 (1 de noviembre de 1985): 2933–39. http://dx.doi.org/10.1139/v85-486.

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Ternary diffusion coefficients can be determined from restricted-diffusion experiments by evaluating zeroth and first time moments of the difference in a concentration-dependent property measured at two levels along the diffusion column. The method is used to determine ternary diffusion coefficients for aqueous sodium sulfite + sodium hydroxide solutions from conductance measurements. It is shown that these data can be analyzed to obtain the ternary diffusivity of sulfur dioxide in strongly alkaline solutions where sulfite is the major transporting species for the sulfur dioxide component. At high pH values, coupled flow of hydroxide ions leads to a significant increase in the diffusivity of the sulfur dioxide component relative to its diffusivity in pure water. Binary diffusion coefficients for aqueous sodium sulfite solutions are also reported.

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Zakaria, Myrna Nurlatifah, Yusfien Shabrina Putri, Asih Rahaju, Sri Fatmawati y Arief Cahyanto. "Inhibitory effect of calcium hydroxide combined with Nigella sativa against Enterococcus faecalis". Dental Journal (Majalah Kedokteran Gigi) 54, n.º 4 (18 de octubre de 2021): 181. http://dx.doi.org/10.20473/j.djmkg.v54.i4.p181-185.

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Background: Calcium hydroxide is the gold standard medicament for root canal treatment. Enterococcus faecalis, the primary cause of intraradicular persistent endodontic infection, is often identified even after endodontic treatment. Thymoquinone, an active ingredient of Nigella sativa, has an antimicrobial effect on both gram-negative and positive bacteria, including E. faecalis. Purpose: This study aimed to evaluate the inhibitory effect of calcium hydroxide combined with Nigella sativa extract and determine the best ratio for the combined material. Methods: This is an experimental study comprised of six groups (n = 4 per group) based on the material and its ratio, namely; (1) calcium hydroxide; (2) Nigella sativa extract; and groups of the combination of calcium hydroxide and Nigella sativa extract with a ratio (3) 70:30, (4) 50:50, (5) 30:70, (6) 10:90. The inhibitory effect against E. faecalis was evaluated by the agar well diffusion method in Muller–Hinton agar. Observation of the inhibitory zone was performed on the first, third, and seventh days. The collected data were analysed by a one-way ANOVA and LSD post hoc test. Results: Calcium hydroxide has the highest inhibitory effect, and the combination of Nigella sativa extract with calcium hydroxide ratio 50:50 was second. The inhibitory zone of these two groups was significantly higher than in any other group (p<0.05). Conclusion: Nigella sativa extract combine with calcium hydroxide did not enhance calcium hydroxide’s antimicrobial property against E. faecalis. An equal amount of Nigella sativa and calcium hydroxide is the best combination ratio, with a stable effect for up to seven days.

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AKMALIA, Widya Nurul y Trimurni ABIDIN. "Diffusion of calcium ions in one-third of root canals after administration of high molecular Chitosan nanohydroxyapatite medicament (In Vitro)". Journal of Syiah Kuala Dentistry Society 6, n.º 2 (4 de enero de 2022): 92–97. http://dx.doi.org/10.24815/jds.v6i2.24190.

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ABSTRACT Calcium hydroxide is currently the gold standard medicament. Still, it has the disadvantage of leavinga residue on the surface of the root canal wall. Hence, it can interfere with the setting time and adhesion of the sealermaterial to the root canal wall. This study aims to determine the ability of calcium ion diffusion in one-third of theroot canal after administration of nanohydroxyapatite medicament with a different vehicle than calcium hydroxide.This study used 24 mandibular premolars extracted, decorated, and prepared, then grouped into four treatmentgroups. Based on the paired T-test, the study results showed no significant effect of calcium ion diffusion in group B(p = 0.739) on the 7th and 14th days. The ANOVA test results showed no significant difference in calcium ion diffusion between groups A, B, and C. on the 7th day of testing (p=0.773) and the 14th day (p=0.661). In conclusion, there was no effect and difference in the diffusion of calcium ions in the apical third after administration ofmedicament nanohydroxyapatite vehicle bidisstilled water and nanohydroxyapatite vehicle nanochitosan compared tocalcium hydroxide on the 7th and 14th day KEYWORDS: diffusion, calcium hydroxide, ion calcium, nanohydroxyapatite, nano chitosan, vehicle

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Thomas, Pinku T., Jyoti Sumi Issac, Parvathy Girija, Lekshmi S. Chandran, D. S. Arjun y A. J. Siddik. "An in vitro comparison of calcium ions release and diffusion ability of calcium hydroxide-based intracanal medicament in combination with three different vehicles like propolis, chitosan, and propylene glycol". Journal of Conservative Dentistry and Endodontics 27, n.º 2 (febrero de 2024): 190–94. http://dx.doi.org/10.4103/jcde.jcde_258_23.

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Abstract Context: Calcium hydroxide, which is an intracanal medicament, is widely used in endodontics. Improvements can be made to its effectiveness, as calcium hydroxide is dependent on the vehicle. Aim: The study aims to compare and evaluate the release and diffusion ability of calcium hydroxide when mixed with – propolis, chitosan, and propylene glycol. Methods: For this study, 33 single-rooted extracted premolar teeth have been decoronated. After the working length and enlargement of the canals had been established, different preparations of calcium hydroxide with vehicles such as propolis, chitosan, and propylene glycol were loaded into the canals. Atomic absorption spectrophotometry was used to analyze the release of calcium ions in three groups, while a digital pH meter was used to determine an acid change. Results: Atomic absorption spectrophotometry showed sustained releases of calcium ions and the digital pH meter showed increased diffusion capacity in the propylene glycol paste group in comparison to the other two groups. Conclusion: Propylene glycol vehicle made it easier to enter calcium hydroxide into the dentinal tubules.

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Wakasugui, Lucas Takeo, Camila Paiva Perin, Allan Abuabara, Marilisa Carneiro Leão Gabardo, Liliane Roskamp, Flares Baratto-Filho y Natanael Henrique Ribeiro Mattos. "Calcium hydroxide diffusion after agitation of endodontic irrigants". Brazilian Journal of Oral Sciences 22 (19 de junio de 2023): e238670. http://dx.doi.org/10.20396/bjos.v22i00.8668670.

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Aim: To compare the influence of two methods of agitation of endodontics irrigants, by diffusion of calcium hydroxide [Ca(OH)2] through the dentinal tubules, measuring the pH of the medium where they were kept. Methods: Twenty mandibular incisors were prepared using a WaveOne Gold Large file, in a reciprocating movement, and then divided into (n = 10): gutta-percha cone (GPC) or Easy Clean system (ECS) agitation of 1% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. The specimens were filled with Ca(OH)2 paste, placed in flasks with 4 mL of deionized water, and stored in an incubator. The pH was read using a digital pH meter immediately after storage (T0), after 7 (T1), 14 (T2), 21 (T3), and 35 (T4) days. Results: Statistical difference between groups was observed regardless of the day pH was measured (p < 0.01). From T2 on, ECS presented higher pH values in comparison with GPC, with significant difference (p < 0.01). Conclusion: Agitation of endodontic irrigants with ECS enhances the Ca(OH)2 diffusion, providing higher pH values, from the 14th day on, when compared with GPC.

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Kopkova, Elena K. y Dmitriy V. Mayorov. "SORPTION CAPACITY OF Mg-Al LAYERED DOUBLE HYDROXIDES WITH RESPECT TO Co (II), Cu (II), Sr (II) AND Cs (I) IONS". Transactions of the Kоla Science Centre of RAS. Series: Engineering Sciences 3, n.º 3/2023 (14 de abril de 2023): 186–92. http://dx.doi.org/10.37614/2949-1215.2023.14.3.034.

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Mg-Al layered double hydroxides with a hydrotalcite structure have been synthesized. The sorption properties of the synthesized sample with respect to non-ferrous metal ions — Co2+, Cu2+, Sr2+ and Cs+ are investigated. The capacities of the adsorption monolayer of the Mg-Al layered hydroxide sample were calculated, amounting to 2.13, 2.21, 1.88 and 3.48 mmol/g with respect to Co(II), Cu(II), Sr(II) and Cs(I) ions, respectively. It is shown that the sorption process is described by a pseudo-second-order kinetic model and proceeds in a mixed diffusion mode.

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Gorbacheva, T. T., D. V. Mayorov y N. V. Fokina. "Mg – Al layered double hydroxides in the dephosphotation of municipal effluents". Perspektivnye Materialy 5 (2021): 47–57. http://dx.doi.org/10.30791/1028-978x-2021-5-47-57.

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Experimental modeling of phosphates extraction from model solutions and sludge mixture of regional water treatment facilities is carried out. The sorbents used are Mg – Al layered double hydroxides obtained by method of solid-phase synthesis according to patented technology. The experimental data of the PO43– -ions sorption onto Mg – Al LDH most accurately describes by pseudo-first order kinetic model. The process of phosphate ions sorption onto hydroxide form Mg – Al LDH proceeds in a mixed diffusion mode, not only the outer surface of the material, but also the inner surface of the grains is involved in the sorption process. The sorption capacity of the hydroxide form is 49 mg P/g, which corresponds to the average level of phosphorus removal from wastewater achieved in world practice for synthesized analogues. The use of the oxide form obtained by materials calcination during 600 °С increases the efficiency of municipal effluents dephosphotation.

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Abdul Kareem, Mustafa W. y Zainab A. Al Dhaher. "Evaluation of The Antifungal Activity of Nasturtium officinale (watercress) Oil with Calcium Hydroxide against Candida Albicans Isolated from Root Canal". Journal of Baghdad College of Dentistry 33, n.º 4 (15 de diciembre de 2021): 1–5. http://dx.doi.org/10.26477/jbcd.v33i4.3012.

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Background: The interest in herbal extracts as antimicrobial agents has increased over the past few years in endodontic therapy. Nasturtium officinale (watercress) is a promising plant with great medicinal values. This study aimed to investigate the antifungal activity of watercress oil in combination with calcium hydroxide against Candida albicans as intracanal medicament. Materials and Methods: Candida albicans was isolated from patients with necrotic root canal or failed root canal treatment. The sensitivity of Candida albicans to different concentrations of watercress oil extract was determined by using the agar well diffusion method in comparison with calcium hydroxide paste. The agar plate method was used to determine the minimum fungicidal concentration (MFC) of the tested oil against the fungus. The combination of the oil extract of Nasturtium officinale with calcium hydroxide was evaluated and compared to calcium hydroxide paste with iodoform by using the agar well diffusion method. Results: The oil extract exhibited antifungal activity against Candida albicans, this activity was found to be increased as the concentration of extract increased. The tested combination of watercress oil extract with calcium hydroxide revealed larger inhibition zones than the ones formed by each tested agent individually. Conclusion: The oil extract of Nasturtium officinale is active against Candida albicans suggesting its potential to be used as an intracanal medicament alone or in combination with calcium hydroxide.

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Bhoj, Dr Sanket Arjun, Dr Vishal Mahajan, Dr Manjusha Rawtiya, Dr Rajendra Daule, Dr Rohit Dhoot y Dr Rohini Mahajan. "A Comparative Study of ION Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin: An In Vitro Study". Scholars Journal of Dental Sciences 10, n.º 04 (18 de abril de 2023): 74–76. http://dx.doi.org/10.36347/sjds.2023.v10i04.004.

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Background: Intracanal medicaments used during root canal treatment comes in direct contact with cells of pulp and periapical tissues. The antimicrobial property of calcium hydroxide [Ca(OH)2] is broadly utilized. It has the capability to dissolve organic tissues as well as to inactivate bacterial endotoxins. The aim of this in vitro study is ion diffusion from calcium hydroxide with various herbal pastes through dentin. Materials and Methods: Twenty one extracted single-rooted premolar were selected. The crown was transversely sectioned at the CEJ level. Paste was prepared by using 1gm of calcium hydroxide powder and 2mL of solution. Group1-(n=7): Calcium hydroxide-saline paste, Group2 (n=7): Calcium hydroxide-coconut water paste. Group3-(n=7): Calcium hydroxide-Ashwagandha paste; the apical foramen were sealed with epoxy resin. The teeth were placed in containers with 50mL of deionized water for 24, 72, and 168 hours, the pH values of the solution were measured using a pH meter. Results: Coconut water was alkaline in nature initially and after 168 hours, the medium was still alkaline. Ashwagandha was the only herbal preparation that increased the pH up to 168 hours and made the medium alkaline. Saline water preparations were acidic at the start of experiment, increased the pH up to 72 hours, but could not make the medium alkaline. Conclusion: The present study was done with the aim of vehicle used for calcium paste to improve the diffusion capability. Coconut water has a much better composition of minerals like calcium and zinc. The better dif¬fusion ability and marked antimicrobial activity make them the best materials, which can be used as vehicles. Ashwagandha prepara¬tions provided additional benefits of diffusion of ions through the dentinal tubules in a sustained manner (up to 168 hours) in comparison with normal saline.

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Suciu, Ioana, Bogdan Dimitriu, Paula Perlea, Oana Amza, Radita Jivoinovici, Ileana Suciu y Irina Gheorghiu. "The consequences of remaining calcium hydroxide in the root canal". Romanian Journal of Stomatology 62, n.º 1 (31 de marzo de 2016): 15–18. http://dx.doi.org/10.37897/rjs.2016.1.3.

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Germs removal from endodontic system is achieved both by instrumentation, accompanied by the use of endodontic irrigants and in precise situations, by interposing intracanallary medication. Based on these features, an update and overview of the attributes of calcium hydroxide was acquired, emphasizing the need to remove the residue of calcium hydroxide as an important measure before performing root canal long lasting fillings. The persistence of calcium hydroxide residue, after removal the drug medication, interfere with dentinal tubules diffusion of the sealant.

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Shubitidze, M. M., A. B. Adzhieva, N. A. Dadashov, M. T. Bagisheva, K. N. Shcherba, S. M. Solimanov y S. A. Nazhmudinov. "Comparative properties characteristics of the various pastes based on calcium hydroxide". Endodontics Today 18, n.º 1 (29 de abril de 2020): 37–40. http://dx.doi.org/10.36377/1683-2981-2020-18-1-37-40.

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Calcium hydroxide is widely used as a interappointment root canal filling material due to its favorable alkaline effect. It is assumed that the action occurs from the diffusion of hydroxyl ions through the apical foramen. The aim of this article was to review studies of the various properties of pure calcium hydroxide, as well as its commercial analogues.

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Tang, Tang, Wen-Jie Jiang, Lu-Pan Yuan, Shuai Niu, Jin-Song Hu y Li-Jun Wan. "Regulating the charge diffusion of two-dimensional cobalt–iron hydroxide/graphene composites for high-rate water oxidation". Journal of Materials Chemistry A 8, n.º 23 (2020): 11573–81. http://dx.doi.org/10.1039/d0ta03895d.

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The importance of charge diffusion in electrocatalysts is shown by regulating the thickness of CoFe hydroxide nanosheets on graphene. The few-layer nanosheets allow effective charge diffusion, enabling a 2000 mA cm⁻² output at only 1.507 V cost in near-industrial conditions.

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Melia Rodrigo, M., Miguel A. Esteso, Ana C. F. Ribeiro, A. J. M. Valente, Ana M. T. D. P. V. Cabral, Luis M. P. Verissimo, L. Musilova, A. Mracek y Derek G. Leaist. "Coupled mutual diffusion in aqueous paracetamol + sodium hydroxide solutions". Journal of Molecular Liquids 334 (julio de 2021): 116216. http://dx.doi.org/10.1016/j.molliq.2021.116216.

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Zelovich, Tamar y Mark E. Tuckerman. "Water Layering Affects Hydroxide Diffusion in Functionalized Nanoconfined Environments". Journal of Physical Chemistry Letters 11, n.º 13 (9 de junio de 2020): 5087–91. http://dx.doi.org/10.1021/acs.jpclett.0c01141.

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Nakata, Yasushi, Keiji Amitani, Takashi Norisuye y Shinichi Kitamura. "Translational diffusion coefficient of cycloamylose in aqueous sodium hydroxide". Biopolymers 69, n.º 4 (18 de julio de 2003): 508–16. http://dx.doi.org/10.1002/bip.10393.

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Li, Guowan, Zhujian Huang, Chengyu Chen, Hongcan Cui, Yijuan Su, Yang Yang y Lihua Cui. "Simultaneous adsorption of trace sulfamethoxazole and hexavalent chromium by biochar/MgAl layered double hydroxide composites". Environmental Chemistry 16, n.º 1 (2019): 68. http://dx.doi.org/10.1071/en18132.

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Environmental contextWater contamination by antibiotics and heavy metals entails potential risks to both the environment and human health. Composite materials based on MgAl-layered double hydroxides and biochar simultaneously adsorbed the toxic sulfamethoxazole and CrVI metal species. These findings indicate that biochar/metal hydroxide composites could be valuable adsorbents for the simultaneous removal of trace antibiotics and metals from water. AbstractWater contamination by antibiotics and heavy metals has drawn wide attention because of the potential risks it poses to both the environment and human health. In this study, a series of adsorbents was successfully synthesised based on MgAl-layered double hydroxides (LDHs) and biochar (BC) derived from Pennisetum sinese Roxb. The batch adsorption experiment results showed that the obtained composites could effectively adsorb trace sulfamethoxazole (SMX) and CrVIsimultaneously. The simultaneous adsorption of trace SMX and CrVI are well described by the pseudo-second-order kinetics and Freundlich isotherm models. Characterisation of the composites after adsorption showed that the composites adsorbed SMX mainly by π-π bonds, hydrophobic interactions and hydrogen bonds. Electrostatic interaction, anion exchange, intraparticle diffusion and hydrogen bonding are the main mechanisms for CrVI adsorption onto the composites. This study indicates that the biochar/MgAl layered double hydroxide composites are promising adsorbents for the simultaneous removal of trace antibiotics and CrVI.

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Al Akhrass, Ghida A., Manal Ammar, Houssam El-Rassy y Mazen Al-Ghoul. "Self-assembled lanthanum hydroxide microspheres within a reaction–diffusion framework: synthesis, characterization, control and application". RSC Advances 6, n.º 5 (2016): 3433–39. http://dx.doi.org/10.1039/c5ra22692a.

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Bae, Sangmi, Ji-Hyun Cha, Jong Hyeon Lee y Duk-Young Jung. "Nanostructured cobalt hydroxide thin films as high performance pseudocapacitor electrodes by graphene oxide wrapping". Dalton Transactions 44, n.º 36 (2015): 16119–26. http://dx.doi.org/10.1039/c5dt02161h.

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Zhou, Xing, Xiaohui Li, Dejian Chen, Danyang Zhao y Xintang Huang. "Ultrathin CoFe-layered double hydroxide nanosheets embedded in high conductance Cu3N nanowire arrays with a 3D core–shell architecture for ultrahigh capacitance supercapacitors". Journal of Materials Chemistry A 6, n.º 47 (2018): 24603–13. http://dx.doi.org/10.1039/c8ta09442j.

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Lizarazo Marriaga, Juan y Peter Claisse. "The influence of the blast furnace slag replacement on chloride penetration in concrete". Ingeniería e Investigación 31, n.º 2 (1 de mayo de 2011): 38–47. http://dx.doi.org/10.15446/ing.investig.v31n2.23463.

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Corrosion of steel reinforcement due to chloride penetration is the greatest cause of durability problems in concrete; intense international research has been carried out to understand and avoid this. This paper summarises the results of a theoretical and experimental research programme investigating the influence of blast furnace slag on chloride-related transport properties. The relationship between the apparent chloride diffusion coefficient, electrical resistivity and compressive strength was measured. Chloride, hydroxide, sodium and potassium's intrinsic diffusion coefficients were obtained by using a computational model and an electrical migration test. The initial hydroxide composition of the pore solution, porosity and chloride binding capacity were also determined from the model. The results showed that blast furnace slag improved chloride penetration resistance, resulting in concrete which was less vulnerable to corrosion.

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Avinash, Alok, Harsha Munot, Rashmi Baranwal, Vijay Duggi, Alok Dubey y Sulabh Pagaria. "Propolis: A Smart Supplement for an Intracanal Medicament". International Journal of Clinical Pediatric Dentistry 10, n.º 4 (2017): 324–29. http://dx.doi.org/10.5005/jp-journals-10005-1459.

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ABSTRACT Introduction One of the most important factors for successful endodontic therapy is root canal cleaning. The difficulty involved in eliminating microorganisms, as well as their residual presence, warrants the use of root canal dressings after biomechanical preparation. Aim The aim of the study was to compare the diffusion ability between nonalcoholic calcium hydroxide—propolis paste, calcium hydroxide—saline paste, and calcium hydroxide—propylene glycol paste. Materials and methods For this proposed study, single-rooted extracted permanent teeth were randomly divided into three groups to fill the canals: group I: Calcium hydroxide—propylene glycol paste, group II: Calcium hydroxide—saline paste, and group III: Calcium hydroxide—propolis paste. After complete filing of the root canal, the pH values of the solutions in the flasks are measured at an interval of 3, 24, 72, 168 hours. Results After 168-hour interval, it was noticed that the mean pH obtained by calcium hydroxide—propolis paste was 10.54 (± 0.38), which was greater than calcium hydroxide—propylene glycol paste 9.70 (± 0.45) and calcium hydroxide—saline paste 9.16 (± 0.30) consecutively. Conclusion The nonalcoholic calcium hydroxide—propolis paste used during the study was able to diffuse through the dentinal tubules. Thus, it can be used as a vehicle for calcium hydroxide. How to cite this article Baranwal R, Duggi V, Avinash A, Dubey A, Pagaria S, Munot H. Propolis: A Smart Supplement for an Intracanal Medicament. Int J Clin Pediatr Dent 2017;10(4):324-329.

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Bhawalkar, Abhilasha, Shreya Gulati, Sanjyot Mulay y Rajesh Shetty. "Antibacterial effectiveness of natural products alone and in combination with Calcium Hydroxide as Intracanal Medicaments : An In-Vitro Microbiological Study". Journal of Ayurveda and Integrated Medical Sciences (JAIMS) 5, n.º 06 (25 de diciembre de 2020): 82–86. http://dx.doi.org/10.21760/jaims.5.6.10.

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Major objective of root canal treatment is disinfection of the root canal system and elimination of microbiota. Various intracanal medicaments as an adjunct to mechanical disinection and irrigation have been used but due to the harmful effects of the commercially available agents, a need for natural alternatives is felt over the time. This in-vitro study aims to evaluate the antibacterial effectiveness of natural agents Septillin and Aloe vera with Calcium hydroxide and without Calcium hydroxide on the Streptococcus mitis, E. Faecalis and Candida albicans using agar well diffusion method. The antibacterial activity was assessed by the diameter of zone of inhibition seen as clear zone around the wells. The study showed that Septillin in combination with Calcium hydroxide and alone showed considerable antimicrobial activity against Streptococcus mitis, Enterococcus faecalis and Candida albicans where as Aloe vera with Calcium hydroxide showed to be mildly effective against all three but not as effective as Septillin and Calcium hydroxide when tested alone.

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Estrela, Carlos, Cyntia Rodrigues de Araújo Estrela, Augusto César Braz Hollanda, Daniel de Almeida Decurcio y Jesus Djalma Pécora. "Influence of iodoform on antimicrobial potential of calcium hydroxide". Journal of Applied Oral Science 14, n.º 1 (enero de 2006): 33–37. http://dx.doi.org/10.1590/s1678-77572006000100007.

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The purpose of this research was to verify the influence of Iodoform on antimicrobial potential of calcium hydroxide. S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans were the biological indicators. The substances tested were: calcium hydroxide + saline; calcium hydroxide + Iodoform + saline; Iodoform + saline. For the agar diffusion test, 18 Petri plates with 20 ml of BHI agar were inoculated with the microbial suspensions. Fifty-four cavities were made and filled with the substances tested. The diameters of microbial inhibition were then measured. In direct exposure test, 162 #50 sterile absorbent paper points were immersed in the experimental suspensions for 5 min, and covered with the pastes. At intervals of 24, 48 and 72 hours, the paper points were immersed in 10 ml of Letheen Broth, followed by incubation at 37°°C for 48h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1 ml inoculum obtained from the Letheen Broth was transferred to 7 ml of BHI, and incubated at 37°°C for 48h. Bacterial growth was again evaluated by turbidity of the culture medium. The calcium hydroxide associated with the saline or the iodoform plus saline showed antimicrobial effectiveness in both experimental methods. The iodoform paste presented antimicrobial ineffectiveness for the agar diffusion test on all biological microorganisms and for the direct exposure test on B. subtilis and on the mixture.

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Kim, Young C., Brian L. Chaloux, Debra R. Rolison, Michelle D. Johannes y Megan B. Sassin. "Molecular dynamics study of hydroxide ion diffusion in polymer electrolytes". Electrochemistry Communications 140 (julio de 2022): 107334. http://dx.doi.org/10.1016/j.elecom.2022.107334.

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ROBERT, G., F. LIEWEHR, T. BUXTON y J. MCPHERSONIII. "Apical Diffusion of Calcium Hydroxide in an in vitro Model". Journal of Endodontics 31, n.º 1 (enero de 2005): 57–60. http://dx.doi.org/10.1097/01.don.0000134211.85578.38.

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Motupally, Sathya, Christopher C. Streinz y John W. Weidner. "Proton Diffusion in Nickel Hydroxide: Prediction of Active Material Utilization". Journal of The Electrochemical Society 145, n.º 1 (1 de enero de 1998): 29–34. http://dx.doi.org/10.1149/1.1838205.

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Dayeh, Malak, Manal Ammar y Mazen Al-Ghoul. "Transition from rings to spots in a precipitation reaction–diffusion system". RSC Adv. 4, n.º 104 (2014): 60034–38. http://dx.doi.org/10.1039/c4ra11223g.

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We report for the first time the transition from rings to spots with squared/hexagonal symmetry in a periodic precipitation system, which consists of sulfide/hydroxide ions diffusing into a gel matrix containing dissolved cadmium(ii) ions.

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34

Bena, Asarizka, Agus Subiwahjudi y Setyabudi Setyabudi. "Perbedaan Daya Antibakteri Antara Kombinasi Calcium Hydroxide-Based Sealer-Amoxicillin Dan Resin-Based Sealer-Amoxicillin Terhadap Bakteri Enterococcus Faecalis". Conservative Dentistry Journal 8, n.º 1 (4 de diciembre de 2019): 1. http://dx.doi.org/10.20473/cdj.v8i1.2018.1-4.

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Background. About 24-77% of root canal treatment failure cases are caused by infection of Enterococcus faecalis due to the resistance factor and virulence of these bacteria. Calcium hydroxide-based sealer and resin-based sealer are two types of sealer often used for root canal obturation due to their antibacterial properties. But the antibacterial properties owned by calcium hydroxide-based sealer has no effect on Enterococcus faecalis. Therefore, the adjunct of local antimicrobial such as amoxicillin is needed to increase antibacterial activities of root canal obturation materials (sealers) especially for calcium hydroxide-based sealer. Purpose. The aim of this study was to compare the effectiveness of antibacterial activity of calcium hydroxide-based sealer-amoxicillin and resin-based sealer-amoxicillin against Enterococcus faecalis. Methods. This study is an experimental laboratory with post test only control group design using Enterococcus faecalis ATCC 29212. Agar diffusion test was used to check the antimicrobial activity of calcium hydroxide-based sealer-amoxicillin and resin-based sealer-amoxicillin. by measuring the inhibition zone diameter of each treatment. Results. Resin-based sealer-amoxicillin’s diameter of zone inhibition is 37,3 mm and calcium hydroxide-based sealer-amoxicillin’s diameter is 18,7 mm. Conclusion. Antibacterial activity of resin-based sealer-amoxicillin is significantly greater than calcium hydroxide-based sealer-amoxicillin.

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Lačević, Amela, Edina Vranić y Irfan Zulić. "Clinical application of calcium hydroxide in dental pathology and endodontics". Bosnian Journal of Basic Medical Sciences 3, n.º 4 (20 de noviembre de 2003): 26–29. http://dx.doi.org/10.17305/bjbms.2003.3488.

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Calcium hydroxide has a hard tissue inducing effect. It is a powder, that can be mixed with a physiological saline to a paste. The paste is highly alkaline with a pH 12.5 and its application to the pulp results in necrosis of the part of coronal pulp tissue shows no or only a milled inflammatory reaction. Analyzing the pH and the concentration of calcium ions in the periapical area, it is obvious that at least 2 weeks are necessary for calcium hydroxide bactericide activity. Calcium hydroxide retains its anti-bacterial properties for about two months when placed under a restoration, after which it degrades to calcium oxide and other less effective calcium salts. All calcium hydroxide preparations have a limited shelf life as they eventually turn into calciumoxide. Calcium hydroxide can be used as linings, for indirect and direct pulp cupping, root dressing, root canal sealant, apical closure. The vehicles play a supportive role, giving pastes chemical characteristics such as dissociation and diffusion as well as favoring the correct filling of the root canal which are decisive factors for antimicrobial potential and tissue healing. The mechanism of action of calcium hydroxide on tissues, inducing the deposition of mineralized tissue, is an extremely important aspect for the indication of calcium hydroxide, because it demonstrates biological compatibility of calcium hydroxide.

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Aprilia, Aprilia, Belinda Kusuma y Istien Wardani. "Antibacterial Effectiveness of Calcium Hydroxide Combined with Cresotin against Enterococcus faecalis". Archives of Orofacial Sciences 16, Supp. 1 (22 de septiembre de 2021): 11–15. http://dx.doi.org/10.21315/aos2021.16.s1.3.

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The goal of endodontic treatment is to prevent and control of pulp and periradicular infections. Calcium hydroxide has a beneficial biological property as an intracanal medicament and can be combined with cresotin to disinfect bacteria in root canals, especially Enterococcus faecalis (E. faecalis) which is the most frequently isolated strain in the root canals. The aim of this study was to investigate in vitro the antimicrobial activity of calcium hydroxide, cresotin, and combination calcium hydroxide and cresotin (Ca[OH]2+Cresotin, 1:1 and 1:2) against E. faecalis. Antibacterial activity was determined by the agar diffusion method. The test medicaments were placed inside the hole that made in the inoculated agar medium. The zone of growth inhibition was measured and recorded after incubation for each plate, and the result was analysed statistically with ANOVA. The in vitro antimicrobial effects of combination calcium hydroxide and cresotin (Ca[OH]2+Cresotin, 1:2) has more prominent antimicrobial activity than others, and calcium hydroxide is more effective than cresotin alone. The antimicrobial activity of combined calcium hydroxide and cresotin is more effective in killing E. faecalis in comparison to the other treatments.

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El Sayed, Mohamed, Nikta Ghanerad, Zeinab Shabanpour, Mahin Shabanpoor y Fatemeh Rahimi. "Comparing the Antifungal Effect of Sodium Hypochlorite Gel versus Different Types of Root Canal Medicaments at Different Time Intervals Using the Agar Diffusion Test: An In Vitro Study". International Journal of Dentistry 2021 (13 de diciembre de 2021): 1–10. http://dx.doi.org/10.1155/2021/6550054.

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Aims. The purpose of this study was to compare the antifungal activity of sodium hypochlorite gel to those of four intracanal medicaments at various time intervals. Materials and Methods. The agar well diffusion technique was utilized to test the antifungal activity of the following medicaments against Candida albinans (C. albicans): sodium hypochlorite gel, chlorhexidine gel, calcium hydroxide paste, Ledermix, and Diapex Plus. The inhibition zone related to each medicine was measured in millimeter after 24, 48, and 72 hours of incubation at 37°C. The data were analyzed using one-way ANOVA and Games–Howell tests, at a significance level of P < 0.05 . Results. Except for Ledermix and Diapex Plus, which had no antifungal action, all of the medicaments showed varied inhibitory zones for C. albicans. At all periods, the NaOCl gel had the most significant inhibition zones, followed by the CHX gel and calcium hydroxide. At all time intervals, the NaOCl gel demonstrated comparable antifungal efficacy. When compared to a 24-hour time interval, the CHX gel showed an increased antifungal activity at the 48-hour and 72-hour intervals. Calcium hydroxide, on the other hand, showed a decrease in its antifungal activity at the 72-hour interval. Conclusion. The antifungal activity of sodium hypochlorite gel was the highest among the investigated medicaments. Chlorhexidine gel's antifungal activity improved over time, whereas calcium hydroxide's antifungal activity declined. Diapex Plus and Ledermix did not have any antifungal properties.

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Rezende, Giovanna Pires da Silva Ribeiro de, Luciane Ribeiro de Rezende Sucasas da Costa, Fabiana Cristina Pimenta y Daniela Abrão Baroni. "In vitro antimicrobial activity of endodontic pastes with propolis extracts and calcium hydroxide: a preliminary study". Brazilian Dental Journal 19, n.º 4 (2008): 301–5. http://dx.doi.org/10.1590/s0103-64402008000400003.

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The purpose of this study was to evaluate the antimicrobial activity of two experimental pastes containing propolis extract associated with calcium hydroxide against polymicrobial cultures collected from 16 necrotic and fistulae root canals in primary molars of 4-8-year-old children of both sexes. The agar-well diffusion technique was used to determine the antimicrobial activity of the following pastes: 11.0% ethanolic extract of propolis (EEP) + calcium hydroxide; and 11.0% extract of propolis without ethanol (EP) + calcium hydroxide. EEP, EP and the association of calcium hydroxide and propylene glycol (CHP) was used as the positive control groups, and propylene glycol was used as a negative control group. Friedman and Wilcoxon tests were used to compare the data from the microbial growth inhibition zones (p<0.05). Paste 1 and Paste 2 showed larger growth inhibition zones against microorganisms from root canal samples than CHP (p=0.021 and 0.003, respectively). Paste 2 tended to have larger growth inhibition zones than Paste 1 (p=0.053). The association between propolis and calcium hydroxide was effective in controlling dental infections in vitro.

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Koshel', N. D. y V. A. Kotok. "Estimation of kinetic activity of the NiOOH/Ni(OH)2 solid-state couple". Electrochemical Energetics 10, n.º 2 (2010): 90–95. http://dx.doi.org/10.18500/1608-4039-2010-10-2-90-95.

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The results of protons diffusion mathematical modeling in the crystalline lattice of NiOOH/ Ni(OH)2 are caparisoned with data of experiments on thin (100 μm) porous electrodes. The criterion of nickel hydroxide activity is offered as product of proton diffusion coefficient in the crystalline lattice of NiOOH on the square of specific surface area. It was founded existence of protons migration mechanism in a crystalline lattice under action electric field.

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Santos, Diogo M. F. y César A. C. Sequeira. "Chronoamperometric Determination of Diffusion Coefficients for Borohydride Anions in Sodium Hydroxide Solutions". Defect and Diffusion Forum 273-276 (febrero de 2008): 583–89. http://dx.doi.org/10.4028/www.scientific.net/ddf.273-276.583.

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Chronoamperometry is carried out with a Au disc electrode in alkaline sodium borohydride solutions of varying concentrations and temperatures. By selecting conditions for which the borohydride oxidation is controlled by diffusion, it was possible to deduce diffusion coefficients and activation energies for borohydride concentrations ranging from 0.03 M to 0.12 M, and temperatures ranging from 25 to 65 °C. The estimated parameters were compared with other values reported in the open literature.

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Arsyada, Intan Fajrin, Devi Rianti y Elly Munadziroh. "Antibacterial activity of mixed pineapple peel (Ananas comosus) extract and calcium hydroxide paste against Enterococcus faecalis". Dental Journal (Majalah Kedokteran Gigi) 51, n.º 1 (31 de marzo de 2018): 20. http://dx.doi.org/10.20473/j.djmkg.v51.i1.p20-24.

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Background: Enterococcus faecalis (E. faecalis) is the bacteria most commonly resulting from failed root canal treatment. Intracanal medicament is used to enhance the success of root canal treatment. A material widely used for this purpose is calcium hydroxide. However, its ineffectiveness in eliminating E. faecalis requires the addition of other antibacterial substances, such as iodoform which has the disadvantage of having toxic effects on tissues. Pineapple peel has antibacterial properties because it contains chemical compounds, such as flavonoid, saponin, tannin, as well as the enzyme bromelain. Purpose: The aim of the study was to determine the antibacterial activity of a mixture of pineapple peel extract at 6.25% and 12.5% concentrations and calcium hydroxide paste at a ratio of 1:1 compared to100% calcium hydroxide and a mixture of calcium hydroxide and iodoform paste against E. faecalis. Methods: The research was laboratory-based experiment in nature. Sample groups were divided into two control groups (one featuring100% calcium hydroxide paste and a second featuring a mixture of calcium hydroxide and iodoform paste) and two treatment groups (mixture of pineapple peel extract and calcium hydroxide paste in 6.25% and 12.5% concentrations with ratio 1:1). The method was using agar diffusion. The result data were analyzed by One Way Anova test. Results: The highest average of the inhibitory zone occurred in group with a mixture of pineapple peel extract 12.5% and calcium hydroxide paste while the smallest average was that of group with a mixture of calcium hydroxide and iodoform paste. Conclusion: Mixture of pineapple peel extract in 6.25% and 12.5% concentrations and calcium hydroxide paste ratio 1:1 has higher antibacterial activity than paste of 100% calcium hydroxide and mixture of calcium hydroxide and iodoform paste againts E. faecalis.

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Ding, Yang, Bruno Batista, Oliver Steinbock, Julyan H. E. Cartwright y Silvana S. S. Cardoso. "Wavy membranes and the growth rate of a planar chemical garden: Enhanced diffusion and bioenergetics". Proceedings of the National Academy of Sciences 113, n.º 33 (2 de agosto de 2016): 9182–86. http://dx.doi.org/10.1073/pnas.1607828113.

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To model ion transport across protocell membranes in Hadean hydrothermal vents, we consider both theoretically and experimentally the planar growth of a precipitate membrane formed at the interface between two parallel fluid streams in a 2D microfluidic reactor. The growth rate of the precipitate is found to be proportional to the square root of time, which is characteristic of diffusive transport. However, the dependence of the growth rate on the concentrations of hydroxide and metal ions is approximately linear and quadratic, respectively. We show that such a difference in ionic transport dynamics arises from the enhanced transport of metal ions across a thin gel layer present at the surface of the precipitate. The fluctuations in transverse velocity in this wavy porous gel layer allow an enhanced transport of the cation, so that the effective diffusivity is about one order of magnitude higher than that expected from molecular diffusion alone. Our theoretical predictions are in excellent agreement with our laboratory measurements of the growth of a manganese hydroxide membrane in a microfluidic channel, and this enhanced transport is thought to have been needed to account for the bioenergetics of the first single-celled organisms.

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Sapna, Hegde, Lala Priti Kamlesh, B. Dinesh Rao y AB Shubha. "An in vitro Evaluation of Antimicrobial Efficacy of Primary Root Canal Filling Materials". Journal of Clinical Pediatric Dentistry 37, n.º 1 (1 de septiembre de 2012): 59–64. http://dx.doi.org/10.17796/jcpd.37.1.v6305588xw525505.

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Objective: The present study aimed to evaluate and compare six different materials commonly used for filling the root canals of primary teeth for antimicrobial efficacy against some of the microorganisms commonly found in infected root canals. Study design: In this experimental in vitro study six root canal filling materials were tested for antimicrobial efficacy against eight microbial strains using the agar diffusion method. Results: Zinc oxide eugenol paste exhibited the strongest antimicrobial potential followed by Endoflas™, zinc oxide-calcium hydroxide-sodium fluoride mixture, zinc oxide-calcium hydroxide mixture and calcium hydroxide paste (Apexcal™). The addition of sodium fluoride to the zinc oxide-calcium hydroxide mixture enhanced the antimicrobial efficacy. Metapex™ demonstrated minimal inhibition and Vaseline™ was non-inhibitory. Conclusions: All the test filling materials demonstrated varying antimicrobial activity against the microorganisms tested. Zinc oxide eugenol paste and materials containing zinc oxide were found to be more effective against the microorganisms compared to materials without zinc oxide.

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Karibayev, M., D. Bekeshov, B. Myrzakhmetov, S. Kalybekkyzy, Y. Wang, Zh Bakenov y A. Mentbayeva. "Effect of Hydration on the Intermolecular Interaction of Various Quaternary Ammonium Based Head Groups with Hydroxide Ion of Anion Exchange Membrane Studied at the Molecular Level". Eurasian Chemico-Technological Journal 25, n.º 2 (15 de julio de 2023): 89. http://dx.doi.org/10.18321/ectj1499.

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Currently, the main limitation of Anion Exchange Membrane Fuel Cells is related to their low chemical stability under alkaline conditions due to the degradation of quaternary ammonium-based head groups, which lowers the transportation of hydroxide ions as well. The knowledge of the intermolecular interaction of various quaternary ammonium head groups with hydroxide ions is the key to improving hydroxide ion’s diffusivity and chemical stability of various quaternary ammonium-based head groups. Consequently, the intermolecular interaction of hydroxide ions with different quaternary ammonium head groups of anion exchange membranes is investigated at the different hydration levels via classical all-atom Molecular Dynamics and molecular well-tempered MetaDynamics simulation methods in this work. Several quaternary ammonium head groups (a) pyridinium, (b) 1,4-diazabicyclo [2.2.2] octane, (c) benzyltrimethylammonium, (d) n-methyl piperidinium, (e) guanidium, and (f) trimethylhexylammonium were investigated in detail. Classical all-atom molecular dynamic simulations illustrate that the results of radial distribution function between the nitrogen atoms of six different quaternary ammonium head groups and hydroxide ion are as follows: (a) > (c) ≥ (f) > (d) > (e) > (b). In addition, from the diffusion coefficient values it was found that the mobility of hydroxide ion by quaternary ammonium head group (f) was lower than (c) at the different hydration levels.

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Batista, Victor Eduardo de Souza, Douglas Dáquila Olian y Graziela Garrido Mori. "Diffusion of Hydroxyl Ions from Calcium Hydroxide and Aloe vera Pastes". Brazilian Dental Journal 25, n.º 3 (julio de 2014): 212–16. http://dx.doi.org/10.1590/0103-6440201300021.

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This study evaluated the diffusion through the dentinal tubules of hydroxyl ions from different calcium hydroxide (CH) pastes containing Aloe vera. Sixty single-rooted bovine teeth were used. The tooth crowns were removed, the root canals were instrumented and the specimens were assigned to 4 groups (n=15) according to the intracanal medication: Group CH/S - CH powder and saline paste; Group CH/P - CH powder and propylene glycol paste; Group CH/A - calcium hydroxide powder and Aloe vera gel paste; Group CH/A/P - CH powder, Aloe vera powder and propylene glycol paste. After placement of the root canal dressings, the teeth were sealed coronally and apically with a two-step epoxy adhesive. The teeth were placed in identified flasks containing deionized water and stored in an oven with 100% humidity at 37 °C. After 3 h, 24 h, 72 h, 7 days, 15 days and 30 days, the deionized water in the flasks was collected and its pH was measured by a pH meter. The obtained data were subjected to statistical analysis at a significance level of 5%. The results demonstrated that all pastes provided diffusion of hydroxyl ions through the dentinal tubules. The combination of Aloe vera and CH (group CH/A) provided a constant release of calcium ions. Group CH/A/P showed the highest pH at 24 and 72 h. In conclusion, the experimental pastes containing Aloe vera were able to enable the diffusion of hydroxyl ions through the dentinal tubules.

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Caicedo, Ricardo, Donald E. Mercante y Dominick J. Alongi. "Calcium-Ion Diffusion of Four Calcium-Hydroxide-Based Materials : Ultracal XS, Vitapex, Roeko Calcium-Hydroxide Plus Points, and Pure Calcium Hydroxide Through Radicular Dentin". International Journal of Oral-Medical Sciences 3, n.º 2 (2004): 75–82. http://dx.doi.org/10.5466/ijoms.3.75.

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Dubey, Vikas y Snehasis Daschakraborty. "Translational Jump-Diffusion of Hydroxide Ion in Anion Exchange Membrane: Deciphering the Nature of Vehicular Diffusion". Journal of Physical Chemistry B 126, n.º 12 (16 de marzo de 2022): 2430–40. http://dx.doi.org/10.1021/acs.jpcb.2c00240.

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Kriplani, R., N. Thosar, M. S. Baliga, P. Kulkarni, N. Shah y R. Yeluri. "Comparative Evaluation of Antimicrobial Efficacy of Various Root Canal Filling Materials Along with Aloevera Used in Primary Teeth: A Microbiological Study". Journal of Clinical Pediatric Dentistry 37, n.º 3 (1 de abril de 2013): 257–62. http://dx.doi.org/10.17796/jcpd.37.3.j62u53q2300484x5.

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Aim: this study was conducted to evaluate the antimicrobial effectiveness of 6 root canal filling materials and a negative control agent against 18 strains of bacteria isolated from infected root canals of primary molar teeth using agar diffusion assay. Materials: Aloevera with sterile water, Zinc oxide and Eugenol, Zinc oxide-Eugenol with aloevera, Calcium hydroxide and sterile water, Calcium hydroxide with sterile water and aloevera, Calcium hydroxide and Iodoform (Metapex) and Vaseline (Control). MIC and MBC of aloevera was calculated. Results: All materials except Vaseline showed varied antimicrobial activity against the test bacterias. The zones of inhibition were ranked into 4 inhibition categories based on the proportional distribution of the data. All the 18 bacterial isolates were classified under 2 groups based on Gram positive and Gram negative aerobes. Statistical analysis was carried out to compare the antimicrobial effectiveness between materials tested with each of the bacterial groupings. Conclusion: Aloevera + Sterile Water was found to have superior antimicrobial activity against most of the microorganisms followed by ZOE + Aloevera, calcium hydroxide + Aloevera, ZOE, calcium hydroxide, Metapex in the descending order and Vaseline showed no inhibition.

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Sripiboon, Siriporn y Panida Charnkeitkong. "Potassium Hydroxide Activation as an Adsorbent for Kinetic Models of Hexavalent Chromium Adsorptions onto <i>Garcinia mangosteen</i> Shell". Materials Science Forum 1086 (27 de abril de 2023): 115–22. http://dx.doi.org/10.4028/p-gw4opv.

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The utilized adsorption kinetic models, i.e., pseudo-zero order, pseudo-first-order, pseudo-second order, intraparticle diffusion, Bangham’s pore diffusion, liquid film diffusion, modified Freundlich and Elovich models have been cultivated the hexavalent chromium adsorption process. A high correlation coefficient (R2) and a small residual root mean square error (RMSE) and Chi-square (χ2) can be depicted in the pseudo-first order for the kinetic adsorption process of hexavalent chromium adsorption on the activated mangosteen shell with potassium hydroxide and carbonized at 400 °C for 2 h as a biochar adsorbent which has a specific surface area of 164 m2/g.

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Guerreiro-Tanomaru, Juliane Maria, Daniele Guidette Chula, Regina Karla de Pontes Lima, Fábio Luis Vilela Camargo Berbert y Mário Tanomaru-Filho. "Release and diffusion of hydroxyl ion from calcium hydroxide-based medicaments". Dental Traumatology 28, n.º 4 (25 de enero de 2012): 320–23. http://dx.doi.org/10.1111/j.1600-9657.2011.01112.x.

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