Addition Of Calcium Research Articles

Preparation of mixed spinel catalyst support (CaxMg1-xAl2O4) reinforced by calcium oxide toward in the biodiesel production from vegetable oil

ABSTRACT A number of CaxMg1-xAl2O4 supports with different amounts of calcium were synthesized by the solution combustion method. Then, calcium oxide was placed on the support by the impregnation method. The synthesized catalysts were evaluated by various physico-chemical analyzes, and their catalytic performance in a biodiesel production system was probed. The results showed that the addition of calcium to the support could improve the physicochemical properties. The conversion of 93.3% was obtained using optimum catalyst (CaO/Ca0.2Mg0.8Al2O4) at the conditions of 100°C, 12 molar ratio of methanol to oil, 3 wt. % of catalyst, and 3 h of reaction time.

The Studies of Sepharose-Immobilized Lipases: Combining Techniques for the Enhancement of Activity and Thermal Stability

Thermal stability is one of the essential parameters characterizing biocatalysts with potential applications in the chemical and pharmaceutical industries. Therefore, it is extremely important to develop standardized procedures for enzyme stability studies. The paper attempts to assess the thermal stability of immobilized lipases in aqueous buffers: lipase B from Candida antarctica (CALB) and lipase from Candida rugosa (CRL-OF) immobilized on the Octyl-Sepharose CL-4B carrier. As part of the optimization conditions of the immobilization, the influence of time on the catalytic activity and lipase loading, as well as the effect of temperature on lipase activity (optimal incubation—14 h at 4 °C), was determined. The thermal stability test procedure was carried out for 7 days using a climatic chamber (65 °C) and a refrigerator (4 °C). The studies of immobilized lipases included the assessment of the impact of various solvents (water, citrate buffer, 1,2-dichloropropane—DCP), temperature, light in the visible spectral range (400–800 nm), and additions of calcium ions. The highest value of residual activity (564.5 ± 21.6%) was received by storing the immobilized CALB in citrate buffer (pH 4.0, 500 mM) with the addition of calcium ions (Ca2+). On the other hand, residual activity values for immobilized CRL-OF after storage in the climatic chamber were lower than 5%. A combining of techniques: immobilization onto the support in high ionic strength and low pH, with a technique of extremally high-temperature applied in a climatic chamber, with the addition of Ca2+ allowed to achieve of excellent thermal stability of the immobilized CALB, with increasing of catalytic activity more than five-fold. Additionally, performing studies on the thermal stability of the tested lipases using a climatic chamber seems to be particularly promising in the context of unifying and standardizing storage guidelines, enabling the comparison of results between different laboratories, as well as enhancing catalytic activity.

Prediction of mechanical strength of magnesium alloy AZ31 with calcium addition using a neural network based model

The aim of the research is to develop a neural network model to predict the mechanical strength of AZ31 magnesium alloy in addition with Calcium. This would help researchers or academicians to fabricate the magnesium alloy AZ31+x wt. % Ca which finds more importance in making biodegradable implants in orthopedic surgery. As the yield strength of human bone lies between 104.9 – 114.3 MPa whereas for pure Mg it is very lesser, it is needed to make alloys suitable for biomedical applications which are to be satisfied with their mechanical properties and biocompatibility. An artificial neural network-based model is used to predict the mechanical properties of Mg alloys AZ31+x wt. % Ca with compositions of Al, Zn, Mn and Ca as countable parts with various proportions. The compositions and properties of twenty different as cast alloys were used for training and prediction of the desired mechanical properties using Artificial Neural Network and the outputs are compared with the experimental results. The results show that the Levenberg-Marquardt (LM) algorithm serves better in prediction of mechanical properties of Mg alloys AZ31 and AZ31+1 wt. % Ca. Also the results were found significant at 90%, 95% and 99% confidence limits.

Effects of calcium supplementation to resuscitation fluids in endurance horses: A randomized, blinded, clinical trial.

The addition of calcium to resuscitation fluids is a common practice in horses, but studies evaluating the effects of calcium supplementation are limited. In healthy horses, decreases in heart rate and changes in serum electrolyte concentrations have been reported. Calcium gluconate administration at a rate of 0.4 mg/kg/min to eliminated endurance horses with metabolic problems will affect heart rate, gastrointestinal sounds, and serum electrolyte concentrations. Endurance horses eliminated from the Tevis Cup 100-mile (160 km) endurance ride for metabolic problems and requiring IV fluid therapy were eligible. Sixteen horses were randomly assigned to receive 0.4 mg/kg/min of calcium (23% calcium gluconate solution) over 1 hour diluted in 10 L of a non-calcium containing isotonic crystalloid (CAL group) or 10 L of a non-calcium containing isotonic crystalloid (CON group). Staff members administering the fluids were blinded to treatment group. Blood samples were collected and physical examinations performed before and after treatment. Heart rates were recorded every 15 min during fluid administration. Data were compared using 2-way analysis of variance (ANOVA) with repeated measures for continuous variables and Fisher's exact test for categorical variables. Calcium was associated with lower heart rates 45 min after starting the infusion (P = .002). Gastrointestinal sounds were less likely to improve in the calcium group compared with the control group (P = .005). An increase in plasma phosphorus concentration (P = .03) was associated with calcium administration. Intravenous calcium supplementation to endurance horses eliminated from competition after development of metabolic problems may decrease heart rate but impairs improvement in gastrointestinal sounds.

Bobot karkas dan persentase potongan karkas itik petelur mojosari yang diberi pakan dengan suplementasi kalsium fitobiotik

Feed additives is important to improve the appearance of duck production. The purpose of this study was to determine the weight and proportion of Mojosari Laying Duck carcass parts that contained calcium phytobiotics. Twenty-four flocks of 120 mojosari laying ducks (24-week-old) were used. Variation Analysis was used to statistically examine the data (ANOVA). Duncan's Multiple Distance Test is used if the study's data show a substantial difference between treatments. A Complete Randomized Design is employed using 6 treatments and 4 tests, each containing 5 mojosari laying ducks. Treatment (P0) is the control feed, (P1) is the control feed plus zinc bacitracin, (P2) is the control feed plus phytobiotics 0.25%, (P3) is the control feed plus phytobiotics 0.50%, (P4) is the control feed plus phytobiotics 0.75%, and (P5) is the control feed plus 1% phytobiotics. The findings demonstrated that the addition of phytobiotic calcium did not significantly affect carcass weight or the percentage of carcass parts (P>0.05). However, (P2) increased the carcass weight compared to the control meal. Weight of the carcass produced is 792.50±91.06 – 972.50±86.84. The percentage of carcasses is 50±0.05 - 57±0.07. The percentage of back pieces was 32.19±1.54 – 36.32±2.94. The percentage of chest pieces was 7.26±0.84 – 8.63±0.97. The percentage of wing pieces was 14.46±0.48 – 13.63±1.93. The percentage of upper thigh pieces produced was 9.50±0.82 – 10.35±2.31, and the percentage of lower thigh pieces was 11.48±0.91 – 13.34±1.97. Results showed that the addition of phytobiotic calcium did not significantly affect the proportion of parts and carcass weight (P>0.05).

Regulation of Calcium Source and Addition Method for MICP in Repairing High-Temperature Concrete Damage

After exposure to high temperatures, the mechanical properties and durability of concrete structures are significantly reduced, and effective measures must be taken for reinforcement and repair. High-temperature concrete damage manifests as looseness, spalling, and cracks, which are suitable for microbial-induced carbonate precipitation. When repairing high-temperature concrete damage with microbial-induced carbonate precipitation (MICP), the calcium source is an important influencing factor. The type of calcium source and the method used to add calcium source will directly affect the mineralized products, which in turn affect the quality of the repair. In this study, the mineralized products of Sporosarcina pasteurii were qualitatively analyzed and the appropriate type of calcium source and addition method were determined. The repair effect on high-temperature concrete damage was also verified. The results showed that the mineralized products of Sporosarcina pasteurii were calcium carbonate, with mixed vaterite and calcite crystals. Calcium acetate was found to be the most appropriate calcium source, while the pre-calcium-source addition method was shown to be optimal. At each damage temperature, the compressive strength showed a certain degree of recovery, and the water absorption exhibited a certain degree of reduction. At 600 °C, the compressive strength of the repaired specimens increased up to 202.68% compared with the damaged specimens and the water absorption of the repaired specimens was 34.32% lower than that of the damaged specimens. The higher the damage temperature, the more obvious the repair effect.

Technological solutions and adaptive processing tools to mitigate the impact of seasonal variations in milk composition on Cheddar cheese production—A review

Variability in milk composition and physicochemical properties impact both manufacturing process performance and the end‐use functionality of cheese. Such variability may be attributed to seasonal calving patterns, production systems, breed, weather patterns, and feed type and significantly impacts concentrations of macro‐ and microconstituents and ultimately cheese composition and quality. This article reviews technological approaches (e.g., milk standardisation protocols and calcium addition), and predictive strategies (e.g., predictive models for coagulation and curd cutting time, in‐line sensors), used to mitigate the effects of seasonal changes in milk composition and their impact on process efficacy and functionality in Cheddar cheese manufacturing.

Effect of calcium levels on structure and function of mitochondria in yeast under high glucose fermentation.

In this study, the effects of calcium levels on structure and function of mitochondria under high glucose environment were studied. In the high glucose environment, yeast growth capacity was inhibited, and intracellular reactive oxygen species (ROS) content was increased from 6 h to 12 h, while ROS content was reduced in group with 1 × 10-1 and 1 g/L CaCl2 level from 24 h to 36 h. Exogenous calcium addition had a significant effect on the elevation of intracellular Ca2+ and cytochrome C content in yeast from 6 h to 12 h; mitochondrial membrane potential decreased with the increase of CaCl2 level under high glucose levels. Mitochondrial swelling of yeast was influenced by high glucose levels and showed a regulatory dynamic change by Ca2+ levels. Isocitrate dehydrogenase activity increased in 1 × 10-3 g/L CaCl2 level from 6 h to 12 h, α-ketoglutarate dehydrogenase activity increased with an increase in CaCl2 level from 6 h to 24 h. Calcium affected the structure and function of mitochondria by regulating the intracellular signal, enzymes in tricarboxylic acid cycle, and cytochrome system of yeast under high glucose stress.

Tracing the Effects of Calcium, Stannum, and Zinc Additions on the Creep Resistance of Mg–Al-Based Alloys

Tracing the Effects of Calcium, Stannum, and Zinc Additions on the Creep Resistance of Mg–Al-Based Alloys

Developmental cadmium exposure disrupts zebrafish vestibular calcium channels interfering with otolith formation and inner ear function

Dizziness or balance problems are estimated to affect approximately 3.3 million children aged three to 17 years. These disorders develop from a breakdown in the balance control system and can be caused by anything that affects the inner ear or the brain, including exposure to environmental toxicants. One potential environmental toxicant linked to balance disorders is cadmium, an extremely toxic metal that occurs naturally in the earth’s crust and is released as a byproduct of industrial processes. Cadmium is associated with balance and vestibular dysfunction in adults exposed occupationally, but little is known about the developmental effects of low-concentration cadmium exposure. Our findings indicate that zebrafish exposed to 10–60 parts per billion (ppb) cadmium from four hours post-fertilization (hpf) to seven days post-fertilization (dpf) exhibit abnormal behaviors, including pronounced increases in auditory sensitivity and circling behavior, both of which are linked to reductions in otolith growth and are rescued by the addition of calcium to the media. Pharmacological intervention shows that agonist-induced activation of the P2X calcium ion channel in the presence of cadmium restores otolith size. In conclusion, cadmium-induced ototoxicity is linked to vestibular-based behavioral abnormalities and auditory sensitivity following developmental exposure, and calcium ion channel function is associated with these defects.

Effect of calcium hydroxide (Ca(OH)2) and magnesium sulfate (MgSO4) on vaname shrimp (Litopenaeus vannamei) cultivation in freshwater media

The purpose of this study was to determine the effect of giving the ratio of Calcium Hydroxide (Ca(OH)2) and Magnesium Sulfate (MgSO4) with different doses on the growth of white shrimp (Litopenaeus vannamei) production in freshwater media. This research was conducted by experimental method using Completely Randomized Design (CRD). The parameter studied was how the effect of the addition of Ca(OH)2 and Magnesium Sulfat (MgSO4) lime with different doses in the maintenance container with 5 treatments and 3 replications, so that 15 experiments were obtained. The treatments applied were: Treatment 1 (P1) Seawater without the addition of calcium and magnesium, P2 Freshwater + 80 ppm Ca(OH)2, P3 Freshwater + 80 ppm Ca(OH)2 and 40 ppm MgSO4, P4 Freshwater + 80 ppm Ca(OH)2 and 80 ppm MgSO4, and P5 Freshwater + 80 ppm Ca(OH)2 and 120 ppm MgSO4. The results showed that the highest survival rate using fresh water was at P4 which was 82%, the specific weight growth rate was 3.9%, and the specific length growth rate was 2.6%. the value of the feed conversion ratio is 0.8. For water quality parameters, the temperature ranges from 30.4-30.60C, water pH 7.2-8.2, DO 6.4-6.6 mg/L, Alkalinity 68-72 ppm, and Ammonia 0.1 mg /L.Keywords: Ca(OH)2; Freshwater; MgSO4; Vannamei Shrimp

Insight into the role of material basicity in the coke formation and performance of Ni/Al2O3 catalyst for the simulated- biogas dry reforming

Biogas, a mixture of methane and carbon dioxide produced from microbial digestion of biomass, waste, or residues, has gained increasing attention from scientists as a valuable resource for producing syngas. This study investigated the effects of different promoters, including calcium, copper, and chromium compounds, on the performance of nickel-based catalysts in biogas reforming. The catalysts were prepared by co-impregnating nickel precursors with the promoters onto the support using the incipient wetness method. The addition of calcium and chromium oxides improved nickel dispersibility, enhanced reducibility, and provided adequate basicity, resulting in superior catalytic activity. Among the promoted catalysts, 0.1Ca–1Ni/Al2O3 demonstrated the best performance with 72% CH4 and 74% CO2 conversions and no significant loss in catalytic activity after 6 h. Additionally, the study found that the basicity of the material was proportional to the transition of amorphous coke into graphitic type, and the advantages and disadvantages of each type of coke were thoroughly discussed.

Production, characterization, and application of a new chymotrypsin-like protease from Pycnoporus sanguineus

Proteases are the most commercialized enzymes and are widely used in industrial processes, especially in the dairy industry. Cheese production is increasing disproportionately to the availability of calf rennet, the main coagulant used in this process. In addition to the cost of rennet, there is also a religious and dietary objection to the use of calf proteases. An alternative is the production of microbial enzymes via solid state fermentation (SSF), which uses agroindustrial residues as a source of nutrients and substrate. To obtain proteases with milk-clotting activity, Pycnoporus sanguineus was produced via SSF using agroindustrial residue wheat bran as the culture medium. Caseinolytic activity and maximum enzyme production were obtained after 96 h of cultivation. The protease was identified as a chymotrypsin-like serine protease after testing it against specific substrates and inhibitors. The protease from P. sanguineus had a specific activity of 741.3 U mg−1 and was able to coagulate reconstituted skim milk and whole milk, with and without the addition of calcium. Coagulation was affected by time, temperature, and calcium and enzyme concentrations. Therefore, we describe herein for the first time a protease obtained from P. sanguineus, a chymotrypsin-like serine protease with milk-clotting activity that has potential applications in the dairy industry.

Effect of calcium hydroxide (Ca(OH)2) and magnesium sulfate (MgSO4) on vaname shrimp (Litopenaeus vannamei) cultivation in freshwater media

The purpose of this study was to determine the effect of giving the ratio of Calcium Hydroxide (Ca(OH)2) and Magnesium Sulfate (MgSO4) with different doses on the growth of white shrimp (Litopenaeus vannamei) production in freshwater media. This research was conducted by experimental method using Completely Randomized Design (CRD). The parameter studied was how the effect of the addition of Ca(OH)2 and Magnesium Sulfat (MgSO4) lime with different doses in the maintenance container with 5 treatments and 3 replications, so that 15 experiments were obtained. The treatments applied were: Treatment 1 (P1) Seawater without the addition of calcium and magnesium, P2 Freshwater + 80 ppm Ca(OH)2, P3 Freshwater + 80 ppm Ca(OH)2 and 40 ppm MgSO4, P4 Freshwater + 80 ppm Ca(OH)2 and 80 ppm MgSO4, and P5 Freshwater + 80 ppm Ca(OH)2 and 120 ppm MgSO4. The results showed that the highest survival rate using fresh water was at P4 which was 82%, the specific weight growth rate was 3.9%, and the specific length growth rate was 2.6%. the value of the feed conversion ratio is 0.8. For water quality parameters, the temperature ranges from 30.4-30.60C, water pH 7.2-8.2, DO 6.4-6.6 mg/L, Alkalinity 68-72 ppm, and Ammonia 0.1 mg /L.Keywords: Ca(OH)2; Freshwater; MgSO4; Vannamei Shrimp

Enhanced oxidation and overheating resistance of the extruded Mg–Zn–Al–Mn magnesium alloy by Calcium addition

Enhanced oxidation and overheating resistance of the extruded Mg–Zn–Al–Mn magnesium alloy by Calcium addition

Experimental Research on Improving Activity of Calcinated Coal Gangue via Increasing Calcium Content.

In this investigation, non-spontaneous combustion coal gangue was activated by two methods: (1) low-temperature calcination and (2) calcium addition. Differences in the activity of the activated coal gangue were studied at various calcination temperatures and amounts of calcium addition. Meanwhile, the cementation activity of the activated coal gangue was evaluated according to the activity effect analysis. Furthermore, the influences of the activated coal gangue on the cementation activity of cement were investigated. The results indicated that the activities of the activated coal gangue increased at a temperature between 500 °C and 700 °C. The calcium addition method can also increase the activity of coal gangue, with the effect being better when the gangue is mixed with slag. The addition of calcium and the calcination of coal gangue can promote the production of active minerals such as metakaolin, which is the main reason for the increased cementation activity.

A Thermodynamic Model to Predict the Composition of Inclusions in Al‐Killed Ca‐Treated Steels

Based on the principle of minimum Gibbs free energy, a thermodynamic model is established to predict the composition of inclusions in the Al‐killed steel during the calcium treatment process. The Wagner model combined with coexistence theory is applied to calculate the Gibbs free energy of the steel‐inclusion system. The composition evolution of inclusions is accurately predicted through the current thermodynamic model which is widely applied to predict the modification of inclusions by the calcium treatment process with different contents of total oxygen (T.O), total sulfur (T.S), and total calcium (T.Ca) in the molten steel. Alumina inclusions can be modified to liquid calcium aluminate inclusions with appropriate T.Ca contents. Solid CaS or CaO inclusions can be formed as a result of the excessive calcium addition to molten steel, while the insufficient calcium addition can hardly modify alumina inclusions to liquid ones. The effect of the T.O and T.S contents on the liquid window is also discussed. The relationship between the value of T.S/T.O in the molten steel and the composition of inclusions is also studied. Based on the established thermodynamic model, a software for the precise control of inclusions is also developed to guide the calcium treatment operation timely in the accrual refining process.

Drying shrinkage behavior of geopolymer mortar based on kaolinitic coal gangue

The coal industry generated tons of waste over the years of mineral extraction, and the waste disposal leads to soil and air pollution caused by acid mine drainage and spontaneous combustion. Seeking environmental sustainability, this paper investigated the valorization of coal tailings as a primary precursor in geopolymer mortar. The effect of Portland cement as a hardened admixture was evaluated on the mechanical and physical properties of geopolymer mortar, by replacing the coal tailings with a lower amount of Portland cement. Six mortars were characterized by several standard tests besides ultrasonic pulse velocity, mercury porosimetry (MIP), and drying shrinkage, the microstructure was evaluated by SEM/EDS analysis and X-Ray diffraction. The workability was slightly higher for geopolymer mortars with calcium by almost 5%, and the addition of sugarcane molasses and flue gas desulfurization increased the fluidity, reaching 220 mm. The Portland cement improved the early strength of geopolymer mortar by almost 10 MPa at 7 days, due to the acceleration of chemical reaction yielding a denser and heterogeneous matrix. The SEM/EDS analysis evidenced the co-existence of the polymeric matrix and C-A-S-H gel. The compressive strength at 28 days was higher than 20 MPa for all geopolymer mortars. A higher reaction rate provided by calcium addition leads to higher densification of the aluminosilicate matrix at early ages. The ultrasonic pulse velocity (UPV) confirmed denser matrix formation, and the geopolymer with 05 wt% of Portland cement presented UPV of 2700 m/s at 07 days, while the non-calcium geopolymer showed 2000 m/s. The denser matrix formed limited the water loss, decreased the open porosity, and improved the stiffness of geopolymer mortars, yielding a drying shrinkage almost 50% lower than for geopolymer without calcium addition. Finally, this paper established the lower replacement (5 wt%) of coal tailings for Portland cement produced efficient geopolymer mortar, with excellent physical and mechanical properties for in situ application without a thermal cure.

Cadmium Transport in Maize Root Segments Using a Classical Physiological Approach: Evidence of Influx Largely Exceeding Efflux in Subapical Regions.

The bidirectional fluxes of cadmium and calcium across the plasma membrane were assessed and compared in subapical maize root segments. This homogeneous material provides a simplified system for investigating ion fluxes in whole organs. The kinetic profile of cadmium influx was characterized by a combination of a saturable rectangular hyperbola (Km = 30.15) and a straight line (k = 0.0013 L h-1 g-1 fresh weight), indicating the presence of multiple transport systems. In contrast, the influx of calcium was described by a simple Michaelis-Menten function (Km = 26.57 µM). The addition of calcium to the medium reduced cadmium influx into the root segments, suggesting a competition between the two ions for the same transport system(s). The efflux of calcium from the root segments was found to be significantly higher than that of cadmium, which was extremely low under the experimental conditions used. This was further confirmed by comparing cadmium and calcium fluxes across the plasma membrane of inside-out vesicles purified from maize root cortical cells. The inability of the root cortical cells to extrude cadmium may have driven the evolution of metal chelators for detoxifying intracellular cadmium ions.

Detection of Gel-Forming Polymers via Calcium Crosslinking, Applied to the Screening of Extracellular Polymeric Substances Extracted from Biological Aggregates.

The valorization of biological aggregates through the extraction of hydrogel-forming polymers can enhance the economics and sustainability of various processes in which bacteria are involved in organic waste transformation, such as wastewater treatment. Achieving these goals requires the development of a method capable of detecting the presence of gel-forming polymers in complex mixtures containing biopolymers that are most often unknown and uncharacterized. A miniaturized screening method capable of detecting gelation via ionic crosslinking using only 1 to 3 mg of the tested samples (commercial molecules or extracellular polymeric substances, EPSs) is proposed. The method consists of calculating a percentage of reactivity (%R) through UV-vis spectra and determining the percentage of gel volume (%Vg) formed after the addition of calcium. Both factors were combined to give a gelling factor (GF), and the test was applied to pure commercial molecules (BSA, DNA, alginate (ALV), and a mixture of them), allowing the classification of the following solutions according to their gel-forming capacity: GF(ALV) > GF(ALV+DNA) > GF(BSA+ALV+DNA) > GF(BSA+ALV) > GF(DNA) > GF(BSA+DNA) > GF(BSA). As a relevant tool for screening hydrogel-forming solutions, the method was applied to the EPS extracted from aerobic granular sludge. The EPS (0.5% w/v) had a GF of 0.16 ± 0.03, equivalent to approximately half of the GF of ALV (0.38 ± 0.02 at 0.5% w/v). The developed test pushes the limits of the existing gel-detection techniques because it allows for quicker, less consuming, and more informative gelation detection through the use of simple methods that do not require sophisticated equipment.