Capping Solution Research Articles

Nutrients Use Efficiency in Coupled and Decoupled Aquaponic Systems

Aquaponics is currently undergoing a transformation into an intensive food production system. The initially applied systems focused on small-scale, fish-centric coupled (CAP, the aquaculture, and the hydroponic units are arranged in a single loop, and the water flows continuously from the fish tanks to the plant unit and back) aquaponics. More recently, the primary area of research interest has shifted toward larger-scale, plant-centric decoupled (aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently) systems, aiming to achieve greater economic benefits and employ more environmentally friendly practices. The objective of this study was to address gaps in the expansion of decoupled larger-scale aquaponics and to provide a comprehensive understanding of the water and nutrient flow in the system. For this purpose, experiments were performed in a greenhouse on CAP and DCAP systems, while this study also included measurements in a pure hydroponic system (HP). This study presents an assessment of the water and nutrient flow in four different crops: basil; cucumber; parsley; and tomato, all co-cultivated with a tilapia aquaculture system. Significant nutrient deficiencies and imbalances were identified in the CAP solution, leading to pronounced impacts on nutrient assimilation, particularly for fruiting vegetables. However, the average nutrient use efficiency (NUE) for nitrogen, phosphorous, potassium, and calcium was found to be 42% higher in the CAP treatment compared to HP and DCAP treatments. The nutrient solution in the DCAP treatment did not exhibit differences in water quality parameters and nutrient efficiency when compared to HP, resulting in similar effects on nutrient assimilation. Nonetheless, it was observed that DCAP plants exhibited superior NUE compared to HP plants.

PENGARUH BRAND IMAGE, KUALITAS PRODUK DAN PROMOSI TERHADAP KEPUTUSAN PEMBELIAN LARUTAN CAP KAKI TIGA DI KOTA PALEMBANG

The purpose of this study was to determine the effect of brand image on the decision of Cap Kaki Tiga solution in Palembang city, to determine the effect of product quality on purchasing decisions of Cap Kaki Tiga solution in Palembang city. To determine the effect of promotion on the purchase decision of Cap Kaki Tiga solution in Palembang city, to determine the effect of brand image, product quality and promotion on the purchase decision of Cap Kaki Tiga solution in Palembang city. This study uses a quantitative data method, namely where the data used in this study analyzes whether there is an influence between brand image, product quality and promotion variables on the purchasing decision of the three-foot cap solution in the city of Palembang. This study uses multiple linear analysis methods using a computer program, namely the software package for the social sciences (SPSS). The results of this study are Brand Image, Product Quality and Promotion Simultaneously (Simultaneously) significantly influence the decision to buy a three-foot cap solution in the city of Palembang.

Plane strain wedge indentation revisited

For a plane strain wedge indentation problem, detailed comparisons between slip-line field theory (SLFT) solutions, experimental observations and finite-element analysis results are carried out. Several past remaining questions on this problem are explored. The finite-element computations appear to account for the nature of a modified slip-line field solution (Petryk H. 1980 Journal de Mécanique Appliquée 4 , 255–282) that assumes the existence of an additional fan-shaped slip-line field just above the boundary between yielding and unyielding regions. For obtuse-angled wedges, finite-element computations show that the indentation load could be smaller for a rough wedge than for a smooth wedge. The question that was raised in the literature with respect to the reversed order of required loads for smooth and rough wedges is not necessarily a paradox. It is revealed that with increasing friction coefficient, a distinct deformation mode resembling the dead metal cap solution in the SLFT is established immediately after passing the critical friction coefficient value at which the contact mode theoretically changes from frictional sliding to perfect sticking. The profiles of the bulged-out lip material remain straight in all the finite-element computations for non-hardening materials. Nonlinearity of the lip profiles frequently observed in experiments appears in the presence of strain hardening or strain-rate sensitivity.

BMP-2 incorporated biomimetic CaP coating functionalized 3D printed Ti6Al4V scaffold induces ectopic bone formation in a dog model

The use of Ti6Al4V in bone engineering is limited, due to the biological inertia of the surface. In this study, a porous Ti6Al4V scaffold with mechanical properties similar to cancellous bone was designed and 3D-printed. Under physiological conditions, the scaffold was immersed firstly in a 5-fold-concentrated simulated body fluid, then ina supersaturated CaP solution containing BMP-2, to form a bone-like porous micro/nano structured biomimetic coating on the surface. Scaffolds were implanted in the muscle pouches created in six beagle dogs and were retrieved four weeks later for histologic and histomorphometric analysis. Results showed that BMP-2 integrated biomimetic CaP coating induced ectopic bone formation, which was absent in other two groups. Soft tissue infiltrated the scaffold's outside 1 mm layer, while the new-formed bone was evenly distributed in the longitudinal and horizontal directions within the rest of the scaffold based on BA/TA, BIC and BA measurements. In conclusion, the BMP-2 incorporated biomimetic CaP coating creates a micro/nano surface structure on the Ti6Al4V scaffold, which helps to increase biocompatibility. The integrated BMP-2 is capable of inducing ectopic bone formation in vivo. The proposed combination may have the potential for bone reconstruction, but further studies are needed to explore its clinical applicability.

Polyaminoacids in Biomimetic Collagen Mineralization: Roles of Isomerization and Disorder in Polyaspartic and Polyglutamic Acids.

The extracellular matrix of hard connective tissues is composed primarily of mineralized collagen fibrils. Acidic noncollagenous proteins play important roles in mediating mineralization of collagen. Polyaspartate, a homopolymer substitute for such proteins, has been used extensively in in vitro models to produce biomimetic mineralized collagen. Polyglutamate behaves differently in mineralization models, despite its chemical similarity. We show that polyaspartate is a 350 times more effective inhibitor of solution precipitation of hydroxyapatite than polyglutamate. Supersaturated CaP solutions stabilized with polyaspartic acid produce collagen with aligned intrafibrillar mineral, while solutions containing polyglutamate lead to the formation of unaligned mineral clusters on the fibril surface. Molecular analysis showed that the commercial polyaspartic acid contains substantial isomerization, unlike polyglutamic acid. Hence, the secondary structure of polyaspartic acid is more disordered than that of polyglutamic acid. The increased flexibility of the polyaspartic acid chain may explain its potency as an inhibitor of solution crystallization and a mediator of intrafibrillar collagen mineralization.

Reliability Study of Polymers Used in Sub-4-μm Pitch RDL Applications

Reliability results obtained on a photosensitive polymer-based redistribution layer (RDL) process with two-metal layers and a target pitch below 4 μm are presented. Fully processed samples have been subjected to 1000 h of high-temperature storage (HTS) performed at 150 °C when a second set of samples endured a temperature-humidity (TH) stress executed at 85 °C and 85 % RH. A thermal cycling (TC) stress between - 50 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C and 125 °C for 1000 cycles was also performed on a third sample set. After 1000 h spent at 150 °C, an increase in the metal line resistivity resulting from copper oxidation by atmospheric oxygen diffusing through the polymer is observed. The oxidation of the top part of the metal lines is further confirmed by failure analyses performed on the stressed samples. Eight different polymers used as a potential capping solution to block the diffusion of oxygen toward the metal lines are investigated. The most promising approach for a reliable polymer-based RDL process involves the use of a mold layer.

Construction of three-dimensional reduced graphene oxide wrapped nZVI doped with Al2O3 as the ternary Fenton-like catalyst: Optimization, characterization and catalytic mechanism.

The rational design and synthesis of novel nanocomposites as effective heterogeneous catalysts is meaningful for the advances in Fenton-like technology. Herein, multiple variants of three-dimensional reduced graphene oxide wrapped nZVI doped with Al2O3 (3D-RGO@nZVI/Al2O3) were prepared by three different self-assembly methods. The composites were characterized by field emission scanning electron microscopy, nitrogen adsorption/desorption isotherms, Raman spectrum analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. A series of experiments on chloramphenicol degradation at different pH values were employed to evaluate the catalytic properties of the prepared catalysts. With the systematical investigation of their morphologies, chemical components and catalytic performance, the optimal 3D-RGO@nZVI/Al2O3 catalyst was synthesized, which was favorable for inducing the Fenton-like reaction by activation of dissolved oxygen (DO) within a wide pH range. The anchored nZVI particles were the main active sites for catalytic oxidation, and doped Al3+ played a major role in buffering the pH of CAP solution. Electron spin resonance spectroscopy revealed the existence of the superoxide radicals (·O2-) and singlet oxygen (1O2), which provides a new insight into the reaction mechanism of reactive oxygen species in the Fenton-like system. This work is an essential effort to explore the promoting effect of synthesis methods on the catalytic behavior of catalysts, and to further study the Fenton-like reaction triggered by DO activation.

Ibandronate-Loaded Carbon Nanohorns Fabricated Using Calcium Phosphates as Mediators and Their Effects on Macrophages and Osteoclasts.

Carbon nanohorns (CNHs), a type of nanocarbon, have been studied for the application of drug delivery systems (DDSs) because they are easily functionalized, support bone regeneration, can be used to perform photohyperthermia, have low toxicity, and are easily phagocytosed by macrophages. To take advantage of these features of CNHs, we developed a DDS for the local treatment of bone metastasis by loading the antibone resorption drug ibandronate (IBN) onto CNHs. The poor adsorption of IBN onto CNHs due to the weak hydrophilic-hydrophobic interaction was overcome by using calcium phosphates (CaPs) as mediators. In the fabrication process, we used oxidized CNH (OxCNH), which is less hydrophobic, onto which IBN was coprecipitated with CaP from a labile supersaturated CaP solution. OxCNH-CaP-IBN composite nanoparticles exerted stronger cell-suppressive effects than OxCNH and IBN in both murine macrophages (RAW264.7 cells) and osteoclasts (differentiated from RAW264.7 cells). OxCNH-CaP-IBN composite nanoparticles were efficiently phagocytosed by macrophage cells, where they specifically accumulated in lysosomes. The stronger cell-suppressive effects were likely due to intracellular delivery of IBN, i.e., the release of IBN from OxCNH-CaP-IBN composite nanoparticles via dissociation of CaP in the acidic environment of lysosomes. Our findings suggest that OxCNH-CaP-IBN composite nanoparticles are potentially useful for the local treatment of metastatic bone destruction.

Sustainability assessment of reactive capping alternatives for the remediation of contaminated marine sediments

The article deals with an original approach, based on sustainability, to select the best reactive capping alternatives for the remediation of contaminated sediments from Mar Piccolo (Italy), one of the most polluted marine ecosystems in Europe. Experimental tests were conducted to assess the capping effectiveness in contaminant sequestration and degradation. The environmental impacts were evaluated by using Life Cycle Assessment, while Multi Criteria Decision Analysis was implemented to consider the stakeholders’ view as well as to identify the best capping solution. The results indicated that the pollutants concentrations in the seawater increase in time without capping, involving possible risks to Mar Piccolo environment. Instead, after capping placement, environmental standards for seawater were always respected. Capping with Activated Carbon and Zero Valent Iron is the best solution for both chemical isolation (efficiency: 95%) and degradation aid (efficiency: 40%). Zero Valent Iron has higher environmental impacts, and it is closely followed by activated carbon and organoclay. The sustainability assessment shows how both the Reactive Permeable Mats with 3 kg/m2 Activated Carbon and Reactive Granular Materials with 5% Activated Carbon are the best solutions for Mar Piccolo remediation. The proposed methodology can be a step towards more sustainable decision making for contaminated sediments remediation.

The Giant Nucleus Impactor (GNI)—A System for the Impaction and Automated Optical Sizing of Giant Aerosol Particles with Emphasis on Sea Salt. Part I: Basic Instrument and Algorithms

AbstractSize distributions of giant aerosol particles (dry radius larger than 0.5μm, sometimes referred to as coarse-mode aerosol particles) are not well characterized in the atmosphere. Measurements are problematic for these particles because they (i) occur in low concentrations, (ii) have difficulty in passing through air inlets, (iii) may be dry or deliquesced particles, and (iv) if sampled by impaction, typically require labor-intensive methods. In this study, a simple, high-volume impaction system called the Giant Nucleus Impactor (GNI), based on free-stream exposure of polycarbonate slides from aircraft, is described along with an automated optical microscope–based system for analysis of the impacted particles. The impaction slides are analyzed in a humidity-controlled chamber (typically 90% relative humidity) that ensures deliquescence of soluble (typically sea salt) particles. A computer-controlled optical microscope with two digital cameras is used to acquire and analyze images of the aerosol particles. At relative humidities above deliquescence (74% RH for sea salt), such particles will form near-spherical cap solution drops on the polycarbonate slides. The sea-salt mass in each giant aerosol particle is then calculated using simple geometry and published water activity measurements. The system has a sample volume of about 10 L s−1at aircraft speeds of 105 m s−1. For salt particles, the measurement range is from about 0.7μm dry radius to at least 16μm dry radius, with a size-bin resolution of 0.2μm dry radius. The sizing accuracy was tested using polystyrene latex (PSL) beads of known size.

Deposition of anti-corrosion hybrid film of hexamethylene diaminetetrakis (methylene phosphonic acid)/hydroxyapatite on biodegradable Mg: Influence of deposition procedures

Magnesium and its alloys are promising biodegradable materials because of their light weight and superior mechanical properties. However, the high corrosion susceptibility of magnesium is the main obstacle that hinders the application of Mg in biomedical applications. In this article, two approaches have been employed to fabricate hybrid films of hexamethylene diamine tetrakis (methylene phosphonic acid) (HMDTMPA) and hydroxyapatite (HA) on Mg. The direct dipping method involves an immersion in a single solution containing both calcium, phosphate, and the organic compound. However, it results in poor-quality loose films, due to unstable film of monocalcium phosphate monohydrate (MCPM). The other method involves immersion in two separated solutions: Ca-P solution and HMDTMPA solution. Our results showed that the corrosion resistance was enhanced about 12-times compared with HMDTMPA film due to the formation of a stable hybrid film of dicalcium phosphate dihydrate (DCPD). The mechanism of formation of anti-corrosion DCPD was discussed on the light of SEM, EDS, FTIR, XRD and XPS.

Role of Magnesium and the Effect of Surface Roughness on the Hydroxyapatite-Forming Ability of Zirconia Induced by Biomimetic Aqueous Solution Treatment.

Zirconia is a well-known bioceramic for dental and orthopedic applications due to its mechanical and aesthetic properties. However, it lacks sufficient bioactivity to bond with the living bone. This study was aimed to induce bioactivity to tetragonal zirconia polycrystal (3Y-TZP) by simple biomimetic aqueous solution treatment. First, hydrofluoric acid (HF) etching was performed to enhance the surface roughness of the 3Y-TZP surface. Then, the samples were treated with two types of aqueous solutions containing calcium and phosphate ions (Ca-P solutions); one solution additionally contained magnesium (Mg) ions and the other without Mg ions. Finally, hydroxyapatite (HAp)-forming ability was evaluated by the conventional simulated body fluid (SBF) test, and the effect of Mg ions on the adhesive strength of the HAp layer to the roughened 3Y-TZP surface was also investigated. The results concluded that there were no noticeable differences in the effect of Mg ions on the HAp-forming ability, and both types of solution treatments resulted in dense HAp formation in 1 day SBF immersion. However, incorporation of Mg ions in one of the Ca-P solutions significantly improved the adhesive strength of the HAp layer to the HF-etched 3Y-TZP substrate compared to the Ca-P solution with no Mg ions.

Antibacterial tooth surface created by laser-assisted pseudo-biomineralization in a supersaturated solution.

A technique for implementing biocompatible and antibacterial functions to a targeted region on tooth surfaces has potential in dental treatments. We have recently demonstrated pseudo-biomineralization, i.e., the growth of an apatite layer on a human dentin substrate by a laser-assisted biomimetic (LAB) process, based on pulsed laser irradiation in a supersaturated CaP solution. In this study, pseudo-biomineralization was induced in the presence of fluoride ions using the LAB process in order to fabricate an antibacterial fluoride-incorporated apatite (FAp) layer on the dentin surface. After processing for 30min, a micron-thick FAp layer was formed heterogeneously at the laser-irradiated solid-liquid interface via pseudo-biomineralization. A time-course study revealed that the LAB process first eliminated the pre-existing organic layer, while allowing fluoride incorporation into the dentin surface within 1min. Within 5min, FAp nanocrystals precipitated on the dentin surface. Within 30min, these nanocrystals acquired a pillar-like structure that was weakly oriented in the direction normal to the substrate surface to form a dense micron-thick layer. This layer was integrated seamlessly with the underlying dentin without any apparent gaps. The FAp layer exhibited antibacterial activity against a major oral bacterium, Streptococcus mutans. The proposed LAB process is expected to be a useful new tool for tooth surface functionalization via facile and area-specific pseudo-biomineralization.

TiO2 encapsulated Au nanostars as catalysts for aerobic photo-oxidation of benzyl alcohol under visible light

Gold nanostar (AuNS) particles, characterized by pointed tips emerging from a central core, exhibit localized surface plasmon resonance (LSPR) with strongly amplified electric field upon illumination. Compared to Au nanospheres and nanorods, the absorbance is enhanced with the absorption band extending from 500 to above 1000 nm. However, they are easily reshaped by Ostwald ripening and therefore difficult to use in any application. This study shows that the AuNS particles can be effectively stabilized by encapsulation with TiO2 using a low temperature method. The synthesis parameters and capping solution were optimized to form nanostars. The encapsulated Au nanoparticles promoted the aerobic oxidation of benzyl alcohol to benzaldehyde at ambient temperature under visible light irradiation. AuNS@TiO2 showed significantly higher photocatalytic activity than Au nanospheres, Au nanorods or bulk TiO2 due to its enhanced LSPR. Encapsulation of the colloidal nanoparticles with TiO2 confers robustness to the resulting heterogeneous catalyst with retention of the metal particle size, morphology and associated LSPR properties.

Tiered CBDC and the Financial System

IT progress and its application to the financial industry have inspired central banks and academics to analyse the merits of central bank digital currencies (CBDC) accessible to the broad public. This paper first reviews the advantages and risks of such CBDC. It then discusses two prominent arguments against CBDC, namely (i) risk of structural disintermediation of banks and centralization of the credit allocation process within the central bank and (ii) risk of facilitation systemic runs on banks in crisis situations. Two-tier remuneration of CBDC is proposed as solution to both issues, and a comparison is provided with a simple cap solution and the solution of Kumhof and Noone (2018). Finally, the paper compares the financial account implications of CBDC with the ones of crypto assets, Stablecoins, and narrow bank digital money, in a domestic and international context.

Role of Capping Material and GaN Polarity on Mg Ion Implantation Activation

Ion implantation of magnesium for p‐type GaN presents many opportunities; however, activation has proven difficult due to the decomposition of GaN at relevant annealing temperatures. Herein, testing the efficacy of multiple in situ and ex situ caps based on aluminum nitride and silicon nitride for GaN protection during annealing is presented. Photoluminescence shows better activation for in situ metal organic chemical vapor deposition (MOCVD)‐grown aluminum nitride caps compared with ex situ sputtered aluminum nitride and the best performance by ex situ plasma‐enhanced chemical vapor deposition (PECVD) silicon nitride. Furthermore, only samples annealed at the highest temperatures tested show preferential growth of UV luminescence to yellow‐green luminescence reinforcing the need for better capping solutions and higher temperature annealing.

Ag Nanoparticle-Decorated Oxide Coatings Formed via Plasma Electrolytic Oxidation on ZrNb Alloy.

Plasma electrolytic oxidation (PEO) can provide an ideal surface for osteogenic cell attachment and proliferation with further successful osteointegration. However, the same surface is attractive for bacteria due to similar mechanisms of adhesion in prokaryotic and eukaryotic cells. This issue requires the application of additional surface treatments for effective prevention of postoperative infectious complications. In the present work, ZrNb alloy was treated in a Ca-P solution with Ag nanoparticles (AgNPs) for the development of a new oxide layer that hosted osteogenic cells and prevented bacterial adhesion. For the PEO, 0.5 M Ca(H2PO2)2 solution with 264 mg L−1 of round-shaped AgNPs was used. Scanning electron microscopy with energy-dispersive x-ray and x-ray photoelectron spectroscopy were used for morphology and chemical analysis of the obtained samples; the SBF immersion test, bacteria adhesion test, and osteoblast cell culture were used for biological investigation. PEO in a Ca-P bath with AgNPs provides the formation of a mesoporous oxide layer that supports osteoblast cell adhesion and proliferation. Additionally, the obtained surface with incorporated Ag prevents bacterial adhesion in the first 6 h after immersion in a pathogen suspension, which can be an effective approach to prevent infectious complications after implantation.

The study of electrodeposition of hydroxyapatite-ZrO2-TiO2 nanocomposite coatings on 316 stainless steel

In this research pure HA and HA-ZrO2-TiO2 nanocomposite coatings (named HZT coatings) were successfully synthesized by merging two usual electroplating methods. In order to deposit pure HA coating a particular saline solution of Calcium and Phosphate was prepared with pH = 4.2, thermodynamically rich of hydroxyapatite. XRD and FTIR studies prove the synthesis of hydroxyapatite during electrodeposition process. To synthesize composite coatings with rational molar ratios of composite agents to matrix, two different concentrations of ZrO2-TiO2 suspensions were added to Ca-P solution at the pH = 4.2 and electrodeposition process done similar to pure HA sample. XRD, FTIR and FESEM (EDS) analyses prove that composite coatings electrodeposited successfully too. The effect of ZrO2-TiO2 composite agents on the characteristics of the coatings were investigated using X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy. Polarization test was carried out to evaluate corrosion behavior of the coatings. In-vitro test was done in SBF solution and bioactivity of coatings was evaluated using FESEM observation.Adding ZrO2-TiO2 nanoparticles makes different changes in the coating specifications. In composite coatings hydroxyapatite has higher crystallinity (92%) rather than pure HA (80%). FESEM observations reveal new morphologies of electrodeposited HA, such as micro-nanorods of HA formed in composite coatings that are not mentioned before in the literature. EDS results show that adding more nanoparticles to the solution results in more nanoparticles deposition in composite coating.The minimum corrosion current density (icorr.) of coatings was for HZT2 composite coating equal to 0.01 μA/cm2 while icorr. of bare substrate was 1.5 μA/cm2 (it means that icorr. of composite coating is 0.007 icorr. of bare substrate.). As a result of nanoparticles addition, porosity is decreased from 46% for HA coating to 6% for HZT2 coating. EIS results show that corrosion resistance of coating increased as a result of adding nanoparticles and HZT2 coating has largest charge transfer resistance among the prepared coatings.The FE-SEM observations suggest that the coatings would demonstrate bioactive behavior because natural hydroxyapatite (deposits formed during immersion) is formed during immersion.

Facile one-pot fabrication of calcium phosphate-based composite nanoparticles as delivery and MRI contrast agents for macrophages

We developed a facile one-pot fabrication process for magnetic iron oxide–calcium phosphate (IO–CaP) composite nanoparticles via coprecipitation in labile supersaturated CaP solutions containing IO nanocrystals. All the source solutions used were clinically approved for injection, including water and magnetic IO nanocrystals (ferucarbotran, used as a negative magnetic resonance imaging (MRI) contrast agent). This ensured that the resulting nanoparticles were pathogen- and endotoxin-free. The dispersants used were clinically approved heparin sodium (heparin) or adenosine triphosphate disodium hydrate (ATP), which were added to the IO-containing labile supersaturated CaP solutions. Both heparin and ATP coprecipitated with CaP and ferucarbotran to form heparin- and ATP-modified IO–CaP nanoparticles, respectively, with a hydrodynamic diameter of a few hundred nanometers. Both the resulting nanoparticles exhibited relatively large negative zeta potentials, caused by the negatively charged functional groups in heparin and ATP, which improved the particle dispersibility when compared to non-modified IO–CaP nanoparticles. The heparin-modified IO–CaP nanoparticles were effectively ingested by murine macrophages (RAW264.7) without showing significant cytotoxicity but barely ingested by non-phagocytotic human umbilical vein endothelial cells, indicating the potential of these nanoparticles for targeted delivery to macrophages. The heparin-modified IO–CaP nanoparticles exhibited a negative contrast enhancing ability for MRI. Our results show that IO–CaP nanoparticles have potential as delivery and MRI contrast agents for macrophages.

Comparative Efficacy of Experimental Solutions in Occluding Dentin Tubules: Calcium Phosphate Based and Oxalate-Based Solutions

To investigate the efficacy in occluding dentin tubules of a modified calcium phosphate based solution supplemented with fluoride and zinc ions (CaP), dentine discs were separately treated with CaP and certain common desensitizing agents including potassium oxalate solution (OX), modified oxalate solutions supplemented with calcium ions (OX/Ca) or phosphate ions (OX/P) for 8 minutes, followed by occluding abilities evaluation with scanning electron microscopy (SEM). CaP showed the highest per cent of sealed dentin tubules and penetrated the most deeply into the tubules, whereas the oxalate modified and unmodified groups showed predominantly open or partially occluded tubules. OX/Ca and OX/P were more efficient in occluding dentin tubules compared with OX. Furthermore, the occluded material obtained with the experimental CaP solutions was more stable (less susceptible to acid dissolution) compared with those from experimental oxalate solutions. Thus CaP could be a new desensitizing agent in dentin hypersensitivity.