Source Of Calcium Ions Research Articles

Inhalable explosive nanosensor for real-time visual monitoring of therapeutic effects of lung cancer

Lung cancer, as one of the major diseases that endanger human health, has a very high fatality rate. Consequently, effective evaluation of clinical treatment outcomes for lung cancer is crucial for the formulation of subsequent treatment plans for patients. In this work, we utilized amorphous calcium carbonate nanoparticles (CaCO3 NPs) as sources of calcium ions (Ca2+) to develop CPs (CaCO3@PDA) core–shell nanoprobes. Concurrently, we functionalized the surface of gold nanoparticles with Cy5.5-peptide, AS1411, and (4-aminosulfonylphenyl) boronic acid (4-APBA) to produce APAAs (Au NPs@pep-AS1411-(4-APBA)), which were further assembled with CPs using PEG to construct an innovative explosive nanosensor, CPAs (CaCO3@PDA-APAAs). The CPs component of the nanosensor could cause the release of a substantial amount of Ca2+ in response to the tumor microenvironment (TME), which in turn induced cellular Ca2+ overload and subsequent apoptosis. This event triggers caspase-3 activation, causing the cleavage of a specific peptide sequence (DEVD), resulting in the fluorescence signal being reinstated. Additionally, the 4-APBA moiety on the probe interacted with H2O2 resulting in alterations in surface-enhanced Raman spectroscopy (SERS) signals, which aided in the detection of reactive oxygen species (ROS) during the physiological processes. By utilizing atomization, the nanoprobes were strategically deposited in the affected lung regions to enhance the fluorescence imaging capabilities and effectively mirror the therapeutic outcomes. Overall, the CPAs explosive nanosensor has a potential in advancing the non-invasive visual monitoring of lung cancer prognosis and can be a valuable tool in ongoing efforts to improve the management of this challenging disease.

EVALUATION OF THE STRUCTURAL-MECHANICAL PROPERTIES OF COMPOSITE PEAR JELLIES PREPARED WITH DIFFERENT GELLING TIME AND CALCIUM SALTS

The aim was to investigate the influence of different calcium salts and gelation times on the structural-mechanical parameters of a pear composite jellies. Calcium citrate and calcium lactate with a concentration of 0.6 % and 1.2 % were used as sources of calcium ions for the gelling time of 24 and 48 h. The changes in the structural-mechanical properties of the jellies were determined from the obtained typical curves through a penetration test using a texture analyzer. The increase in the concentration of calcium ions led to the increasing values of the structuralmechanical parameters of the fruit jellies, except for adhesiveness and rupture deformation. The shape of the penetration curves was determined to a greater extent by the type and concentration of calcium salts and to a lesser extent by the gelation time. The Pearson correlation coefficients for the compressive stress, deformation force and firmness increased compared to the other structural-mechanical properties with an increase in the gelation time and the concentration of calcium salts.

Application of fluidized-bed homogeneous crystallization technology to carbon sequestration and recovery from flue gas

The Earth’s energy balance produced by human activity is the main factor in the complex relationship between greenhouse gases and global warming. The Taiwan Environmental Protection Agency reports that carbon dioxide makes up more than 95% of Taiwan’s most recent greenhouse gas emissions. This study used fluidized-bed homogeneous crystallization (FBHC) technology to recover carbonate in a simulated CO2-enriched flue gas. It was specifically designed to determine how carbonate removal and crystallization efficiency were affected by carbonate surface loading, the influence of the source of calcium ions, and interfering substances. Results revealed that the best surface loading at 55 kg m− 2 h− 1 achieved 93% removal and 84% crystallization efficiency. At 50 mg L− 1 of sulfate ions, the presence of more interfering compounds tends to reduce carbonate removal to 97% and 91% crystallization. Regarding X-ray diffraction data, the recovered carbonate crystals resembled calcium carbonate crystals. It has been demonstrated that carbonate can be recovered using FBHC technology as a method of CO2 capture and storage.

Enhancing biocement precipitation potential of locally isolated soil ureolytic bacteria using seawater

A locally isolated ureolytic bacterial strain, identified as Kurthia zopfii strain Bal19, was retrieved from soil samples taken at Zoo Johor, Malaysia. It demonstrated remarkable biocement precipitation capabilities, yielding 1.23 g/L when combined with seawater, serving as an economical source of calcium ions. This promising performance suggests the viability of using this specific bacterial strain in tandem with seawater for cost-effective biocement precipitation (BCP), offering a compelling alternative to conventional calcium salts like calcium chloride for large-scale biocementation applications in Malaysia.

Silica-Containing Biomimetic Composites Based on Sea Urchin Skeleton and Polycalcium Organyl Silsesquioxane.

The paper presents an original approach to the synthesis of polycalciumorganyl silsesquioxanes through the reaction of polyorganyl silsesquioxanes [RSiO1.5]n (where R is an ethyl and phenyl radical) with sea urchin skeleton under the conditions of mechanochemical activation. The novelty and practical significance of the present study lies in the use of an available natural raw source as a source of calcium ions to initiate the reaction of calcium silicate formation and create a matrix for the formation of a porous inorganic composite framework. The thermal stability of the introduced silicates, i.e., the ability to maintain a porous structure at high temperatures, is key to the production of an ordered porous material. The reaction scheme was proposed to be based on the interaction of calcium carbonate with the siloxane bond. FTIR, XRD, GPC, and TGA were used to study the composition and structure of the obtained materials. The cross-sectional area of the polymer chain and the volumes of the coherent scattering regions of the polymers obtained were calculated from the XRD data. To prepare the composites, the sea urchin skeleton was further modified with polycalciumorganyl silsesquioxanes in a toluene solution. To remove the sea urchin skeleton, the obtained biomimetic composites were treated with hydrochloric acid. The results of the morphological and surface composition studies are reported. The method proposed in the paper could be of fundamental importance for the possibility of obtaining structured porous composite materials for a wide range of practical applications, including for the purpose of creating a composite that may be a promising carrier for targeted delivery of chemotherapy agents.

Fast and efficient green synthesis of CaWO4 NPs using eggshells as a biogenic calcium source: Structure, optical property, and morphology

In summary, we report a fast, easy, and low-cost green synthesis approach to obtain calcium tungstate nanoparticles (CaWO4NPs_GS) using eggshells as a source of calcium by the sonochemistry method at room temperature. These nanomaterials were structurally characterized by X-ray diffraction (XRD) and Rietveld refinement analysis, where a pure phase with very close structural parameters with calcium tungstate nanoparticles was synthesized at the conventional route (CaWO4NPs_CS). All vibrational Raman active modes characteristic of symmetry point C4h6 were confirmed. An optical band gap value (Egap = 3.92(2) eV) for CaWO4NPs_GS lower than for CaWO4NPs_CS (Egap = 3.92(2) eV) was archived, and that is associated with the intermediate electronic levels due to the oxygen vacancy and micro-strain effect. Field Emission Scanning Electron Microscopy (FE-SEM) images show several nanoparticles with a particle size of 62.7 ± 1.3 nm for CaWO4NPs_CS and 48.7 ± 1.2 nm for CaWO4NPs_GS, where all elements characteristic of calcium tungstate (Ca, W, and O) were appointed by Energy Dispersive X-ray (EDX) analysis. While the photocatalytic performance of CaWO4NPs_GS was 2.5 times faster than CaWO4NPs_CS in the photodegradation of Rhodamine B (RhB) dye in an aqueous solution under UV light in 120 min. Therefore, confirming that chicken eggshell is a promissory raw material as a biogenic source of calcium ions for synthesizing calcium tungstate with promissory photocatalytic properties.

In-situ HYDROTHERMAL METHOD FOR GRAPHENE OXIDE/HYDROXYAPATITE SYNTHESIS FROM SCALLOP SHELLS

The graphene oxide/hydroxyapatite composite was synthesized using an in situ hydrothermal method. In this process, scallop shells (Amusium pleuronectes) were used as a source of calcium ions in fabricating the composite. Meanwhile, graphene oxide was exfoliated and oxidized from graphite powder. X-ray diffraction confirms that hydroxyapatite in the composite has a hexagonal structure. Also, the inclusion of graphene into the system did not alter the crystal structure. However, it affected the size of the apatite crystal deposited in the graphene surfaces layer, which was revealed by scanning electron microscopy analysis. The infrared spectra confirm some shiftings of the phosphate bands absorption, indicating electronic interaction between graphene and apatite matrix. Furthermore, from the Electron dispersive X-ray analysis obtained ratio of calcium/phosphate was found to be 1.84.

Preparation and characterization of flame-retardant and thermal insulating bio-based composite aerogels

Biomass aerogels have gotten a lot of attention because of their remarkable characteristics such as high porosity, low thermal conductivity, environmental friendliness, and sustainability. However, the general flammability of biomass raw materials reduces their fire safety. In this study, flame-retardant bio-based composite aerogels are proposed for building energy saving. Alginate is chosen as the basic skeleton. Noncombustible nano calcium carbonate enhances the flame retardancy of the aerogels by serving as a nano-filler. It is also a source of calcium ions to further promote the char formation of the cross-linked alginate network during thermal degradation. Moreover, boric acid is introduced into the cross-linked network to improve thermal stability and char yield. Therefore, the limiting oxygen index of the alginate–calcium carbonate (Alg-CaCO3) composite aerogels reaches up to 39.5 %. The results of thermogravimetric analysis, thermogravimetry-infrared spectrometry, and in-situ diffuse reflectance infrared Fourier transform spectroscopy demonstrate that the Alg-CaCO3 composite aerogels have a significant tendency to form char during thermal degradation. In addition, the Alg-CaCO3 composite aerogels also show high porosity (up to 92.40 %), excellent mechanical properties (compression modulus up to 0.936 MPa), and outstanding heat insulation (thermal conductivity as low as 0.031 W m−1 K−1). Furthermore, natural shells, pearls, and eggshells are adopted to substitute nano-CaCO3 for preparing fully bio-based composite aerogels, which also reflect the promotion effect of fire resistance. Such ultralight flame-retardant thermal insulation material derived from biomass has the potential to be a significant green building material.

Hemostatic Alginate/Nano-Hydroxyapatite Composite Aerogel Loaded with Tranexamic Acid for the Potential Protection against Alveolar Osteitis.

Wound control in patients on anticoagulants is challenging and often leads to poor hemostasis. They have a higher tendency to develop alveolar osteitis after tooth extraction. The application of a hemostatic dressing that has a high absorbing capacity and is loaded with an antifibrinolytic drug could help in controlling the bleeding. Alginate/nano-hydroxyapatite (SA/Nano-HA) composite aerogels loaded with tranexamic acid (TXA) were prepared. Nano-HA served as a reinforcing material for the alginate matrix and a source of calcium ions that helps in blood clotting. It influenced the porosity and the water uptake capacity. TXA release from SA/Nano-HA aerogels showed a biphasic profile for up to 4 h. Blood coagulation studies were performed on human whole blood. The TXA-loaded aerogel significantly reduced the clotting time by 69% compared to the control (p < 0.0001). Recalcification time was significantly reduced by 80% (p < 0.0001). Scanning electron microscopy analysis revealed the porous nature of the aerogels and the ability of the optimum aerogel to activate and adhere platelets to its porous surface. The cell migration assay showed that there was a delay in wound healing caused by the TXA aerogel compared to the control sample after treating human fibroblasts. Results suggest that the developed aerogel is a promising dressing that will help in hemostasis after tooth extraction.

Enzyme-induced carbonate precipitation utilizing fresh urine and calcium-rich zeolites

Enzyme-induced carbonate precipitation (EICP) is a biocementation technique that produces comparatively fewer carbon dioxide emissions than traditional cementation. However, the use of synthetic reagents for EICP is costly, and the process produces an ammonium byproduct that is a water pollutant. This study utilized fresh human urine as a source of urea and calcium-rich zeolites as an ammonium adsorbent and a source of calcium ions for the EICP cementation technique. Batch hydrolysis, adsorption, and biocementation experiments were conducted to determine the effects of zeolite type, zeolite form (i.e., exchangeable ion), ammonium adsorption, and calcium release. The results showed that calcium-rich chabazite adsorbed comparable ammonium ions and released 2.7-times more calcium ions on average than calcium-rich clinoptilolite; calcium-rich chabazite also released calcium ions in excess without the addition of calcium chloride in solution. Additionally, synthetic-fresh urine and real-fresh urine had comparable ammonium adsorption and calcium release trends. Finally, inclusion of a pre-hydrolysis step reduced the ammonium adsorption by 3.9-times; additionally, longer adsorption times led to CaCO3 precipitation outside of the sand column, which is an undesirable outcome for soil biocementation. Even with this limitation, the CaCO3 content of sand columns ranged from 0.48% to 0.92%, which signifies the potential of the proposed process for cementation, given a higher initial concentration of urea. The results from this work show the ability to use both a waste stream, human urine, and a naturally occurring material, zeolites, to greatly reduce the economic and environmental stressors of conventional soil binders for applications such as liquefaction mitigation (e.g., Portland cement) and dust suppression (e.g., synthetic polymers).

Calcium-based coordination polymers from a solvothermal synthesis of HKUST-1 in 3D printed autoclaves

A mixed-metal 1D coordination polymer [CaCu(HBTC)2(H2O)8]n (where H3BTC – benzene-1,3,5-tric arboxylic acid) was obtained in a solvothermal synthesis of a well-known copper-containing metal–organic framework [Cu3(BTC)2(H2O)3]n (HKUST-1) in autoclaves 3D-printed from commercial polypropylene. This material was a source of calcium ions, apparently, leaking from a colorant (calcium carbonate) promoted by glacial acetic acid as a modulator used to produce large single crystals of HKUST-1. This finding was confirmed by elemental analysis and a model experiment that resulted in a new calcium-based 1D coordination polymer [Ca(H2BTC)2(H2O)5]n under the same solvothermal conditions with no copper or calcium salts put into a 3D-printed autoclave.

Structural Characterization of CaF2: Dy Nanoparticles Synthesized by Simple Chemical Co-Precipitation Method

In this work, nanoparticles of dysprosium doped calcium fluoride (CaF2:Dy) has been prepared by Simple Chemical Co-Precipitation Method in which 0.05 mol of CaCL2 is used as the calcium ion source and 0.05 mol of NH4F as the fluoride ion source. 1 mol% of Dy2O3was used as the dopant. The synthesized nanoparticle samples was characterized by X- ray diffraction (XRD) and the crystallite size using the dominant (111) peak was found to be 56.09 nm. SEM image shows the presence of spherical shaped nanoparticles. The PL emissions bands are observed at 479 nm (blue emission peak) and 573 nm (yellow emission peak).

Formulation development and characterization of eplerenone insitu oralgels

Gastro retentive drug delivery systems have been widely used to prolong the retention of dosage forms in the stomach. Among the various approaches, the floating in-situ gelling formulation offers sustained drug release as well as prolonged gastric retention, along with the added advantage of the liquid oral dosage form. The present study was an attempt to formulate and evaluate floating in situ gel of Eplerenone by using various polymers like Xanthan gum, Carbopol, HPMC K100M, and Karaya gum which undergoes pH dependant sol-gel transition at gastric pH, thereby prolonging the retention of the system in the stomach. Sodium alginate a natural polymer was employed as a gelling agent where Gelation is triggered by the source of calcium ions in the form of calcium carbonate. Drug and polymers were subjected for compatibility study using FTIR studies, which revealed that there was no interaction between drugs and polymers. The evaluation was carried out for invitro parameters such as gelling nature, Total floating time, drug content, viscosity, &amp; in vitro dissolution studies. Among all the formulations, the F12 formulation containing HPMC K100M was chosen as an optimized formulation that shows maximum drug release by the end of 12hrs and has excellent floating characteristics and gastric retention. From kinetic studies, the optimized formulation shows zero-order release with super case II transport mechanism.

Study on the Crystal Structure and Genetic Structure of Eggshell

Eggshell provides a relatively independent and stable internal environment for embryo growth and development, and is also a source of calcium ions required for embryo development. Eggshells of good quality can reduce the risk of food safety to a certain extent, and can also reduce the economic losses caused by broken eggshells and improve economic efficiency. At the same time, the process of eggshell formation is also a classic biomineralization model. In this study, the 600K high-density SNP chip of chicken was used to perform SNP typing on several groups obtained by the reciprocal cross between Bailaihang and Dongxiang green-shell hens. Scanning electron microscopy and X-ray crystal diffraction were used to determine the ultrastructure and eggshell ultrastructure. Crystal structure, explain its genetic basis, and explore the relationship between eggshell ultrastructure and crystal structure. This study believes that the DERA gene plays an important role in regulating the growth of eggshell crystals. There are three possible ways of action: one is to provide energy for the synthesis of uterine tissue cell matrix protein and its transport with ions; the second is to reduce the stress of high Ca2+ concentration stress, maintain cell activity, and for the growth of eggshell crystals Stably provide the required Ca2+; third, by regulating the concentration of ATP in the uterine fluid, the effect on the growth of eggshell crystals.

The leaching mechanism of hydraulic mortars as part of autogenic self-healing process

Historic mortars have exhibited long term durability which has been largely attributed to their self-healing properties. The aim of this work is the study of the autogenic self-healing mechanism as observed in historic mortars as well as the simulation of the phenomenon in laboratory prepared lime-pozzolan and natural hydraulic lime mortars. One of the most significant parameters in autogenous self-healing phenomenon is the source of the calcium ions, which controls the formation of new healing phases inside cracks. In this study, an electrochemically accelerated leaching procedure was designed to examine the influence of mineralogy and curing time on the dissolution of Ca-bearing phases of lime-pozzolan and NHL mortars, which are characterized by high portlandite content. It was found that, apart from portlandite, Ca+2 are also leached from C2S and C–S–H phases and it was shown that this phenomenon takes place in two separate time-frames: an early period (t < 28 d), which is controlled by the portlandite content of the binder and, a later period (t > 28 d) where decalcification of C–S–H and dissolution of secondary portlandite are dominant. The phenomenon was further studied on mortar specimens where healing of micro cracks was observed by precipitation of secondary calcite inside cracks and voids, highlighting the role of leached Ca+2 on the autogenic self-healing mechanism. It is proved that, contrary to what is believed about the autogenic healing, besides portlandite, the contribution of hydraulic phases is also significant. Overall, this study confirms the significant role of the Ca-leaching process in the autogenic self-healing mechanism and highlights the different sources of calcium ions, as well as the different time frames of the events. Finally, the findings elucidate the high self-healing potential of traditional mortars which contribute to their prolonged service life.

Microbially Induced Calcium Carbonate Plugging for Enhanced Oil Recovery

Plugging high-permeability zones within oil reservoirs is a straightforward approach to enhance oil recovery by diverting waterflooding fluids through the lower-permeability oil-saturated zones and thereby increase hydrocarbon displacement by improvements in sweep efficiency. Sporosarcina pasteurii (ATCC 11859) is a nitrogen-circulating bacterium capable of precipitating calcium carbonate given a calcium ion source and urea. This microbially induced carbonate precipitation (MICP) is able to infill the pore spaces of the porous medium and thus can act as a potential microbial plugging agent for enhancing sweep efficiency. The following explores the microscopic characteristics of MICP-plugging and its effectiveness in permeability reduction. We fabricate artificial rock cores composed of Ottawa sand with three separate grain-size fractions which represent large (40/60 mesh sand), intermediate (60/80 mesh sand), and small (80/120 mesh sand) pore sizes. The results indicate a significant reduction in permeability after only short periods of MICP treatment. Specifically, after eight cycles of microbial treatment (about four days), the permeability for the artificial cores representing large, intermediate, and small pore size maximally drop to 47%, 32%, and 16% of individual initial permeabilities. X-ray diffraction (XRD) indicates that most of the generated calcium carbonate crystals occur as vaterite with only a small amount of calcite. Imaging by SEM indicates that the pore wall is coated by a calcium carbonate film with crystals of vaterite and calcite scattered on the pore wall and acting to effectively plug the pore space. The distribution pattern and morphology of microbially mediated CaCO3 indicate that MICP has a higher efficiency in plugging pores compared with extracellular polymeric substances (EPSs) which are currently the primary microbial plugging agent used to enhance sweep efficiency.

Modification of Hydraulic Conductivity of Sandy Soil using Seawater and Alkaline Solutions

Altering soil characteristics by precipitation of the calcium carbonate between soil particles is attracting the interest of geotechnical engineers for a wide range of applications. However, current applied approaches still face challenges such as the high cost of materials, difficult handling of precursors, and hazardous by-products. The study described by the current paper investigated the modification of hydraulic conductivity of sandy soil by chemical precipitation of the calcium carbonate using seawater as the source of calcium. The designed experiment involved treatment of bench-scale soil columns by two readily mixed solutions. One of the solutions served as the source of calcium ions and the other contained carbonate ions. The current paper compares behavior of hydraulic reduction considering different resources. The results showed that the crystals formed in small sizes as a result of the instantaneous reaction of calcium precipitation; and thus, crystals transport with the solution as colloids. Accordingly, reductions in hydraulic conductivity were mainly governed by the filtration mechanisms; and the precipitated calcium carbonate was retained close to the injection point. Conducting treatment using seawater as the source for calcium ions induced 65% reduction in hydraulic conductivity at 5.5 g CaCO3/g soil. This reduction is identical to the case when the artificial source was used. Further treatment by the artificial source of calcium reduced the hydraulic conductivity of sandy soil by 97.2%. These outcomes suggest that the chemically induced calcium carbonate precipitation from seawater can be employed by some geo-environmental applications which are conducted in the vicinity of the shore and require reduction of hydraulic conductivity.

Long-lasting chemiluminescence hydrogels made in situ

Alginate, a natural polysaccharide, can form gels with divalent cations under mild conditions. In this paper, homogeneous, injectable chemiluminescence hydrogels were prepared in situ for the first time. The raw materials contained alginate, calcium ion source (CaCO3), d-glucono-δ-lactone (GDL), chemiluminescence reagent (isoluminol), and catalyst (Co2+). When H2O2 was added, the hydrogels would give blue light which was visible to naked eyes. And, the light emission could last for over 10 h due to the slow-diffusion-controlled chemical reaction. In addition, the as-prepared CL hydrogels had a good response capacity to H2O2.

The effect of burnt lime addition on hydration of Ultra-high performance cementitious composites

The paper deals with the burnt lime utilization as a source of calcium ions participated during hydration process of ultra-high performance cementitious composites. These type of ultra-high performance cementitious composites are based on the high content of silica fume that together with calcium ions form the binder phase. In the case of ordinary Portland cement, the hydration during induction period supposed to be too slow for dissolution of required amount of calcium ions necessary for the pozzolanic reaction of presented silica fume. The low addition of the lime should be a sufficient calcium source that allow the starting of the pozzolanic reaction before the acceleration period occurs. The calcium ions content from the beginning of the reaction was controlled by an addition of soft-burnt and dead-burnt lime. Its influence was studied in terms of hydration process by isothermal calorimetry. Based on the experimental data, the hydration reaction mechanism was proposed.

Contactless Stimulation and Control of Biomimetic Nanotubes by Calcium Ion Gradients.

Membrane tubular structures are important communication pathways between cells and cellular compartments. Studying these structures in their native environment is challenging, due to the complexity of membranes and varying chemical conditions within and outside of the cells. This work demonstrates that a calcium ion gradient, applied to a synthetic lipid nanotube, triggers lipid flow directed toward the application site, resulting in the formation of a bulge aggregate. This bulge can be translated in a contactless manner by moving a calcium ion source along the lipid nanotube. Furthermore, entrapment of polystyrene nanobeads within the bulge does not tamper the bulge movement and allows transporting of the nanoparticle cargo along the lipid nanotube. In addition to the synthetic lipid nanotubes, the response of cell plasma membrane tethers to local calcium ion stimulation is investigated. The directed membrane transport in these tethers is observed, but with slower kinetics in comparison to the synthetic lipid nanotubes. The findings of this work demonstrate a novel and contactless mode of transport in lipid nanotubes, guided by local exposure to calcium ions. The observed lipid nanotube behavior can advance the current understanding of the cell membrane tubular structures, which are constantly reshaped during dynamic cellular processes.