ObjectiveThis study aimed to investigate the effect of the interactions among potassium (K), calcium (Ca) and sodium (Na) on cabbage growth and nutrient absorption. MethodA total of 11 treatments with different ...ObjectiveThis study aimed to investigate the effect of the interactions among potassium (K), calcium (Ca) and sodium (Na) on cabbage growth and nutrient absorption. MethodA total of 11 treatments with different levels of K, Ca and Na were set in the pot experiment to measure the nutrient content and uptake in cabbage plants. ResultThe use of K or the combined use of K and Ca improved the cabbage absorption on K and Ca. In addition, K and Ca presented an interaction as that appropriate amount of Ca promoted K uptake while excessive Ca inhibited the uptake. The treatment of Ca 2 K 3 with 0.33 g/pot of Ca and 0.67 g/pot of K could significantly increase the quantity of dry matter accumulation and absorption of Ca and K in cabbage, was the best among all treatments. ConclusionApplication of suitable amount of Ca could release the Na stress on cabbage growth at the low level of Na in soil.展开更多
A field experiment was conducted on a sandy loam soil at an Experimental Farm in Taejon, South Korea, to determine the effects of paper mill sludge compost application rates on K, Na, Ca and Mg concentrations of soybe...A field experiment was conducted on a sandy loam soil at an Experimental Farm in Taejon, South Korea, to determine the effects of paper mill sludge compost application rates on K, Na, Ca and Mg concentrations of soybean (Glycine max (L.) Merr.) aboveground tissues and the genotypic effects on the concentrations of these elements. Sludge compost treatments of 0, 75, and 150 t ha-1 were applied to 30 diverse soybean cultivars. Concentrations of K, Na, Ca, and Mg in aboveground tissues harvested 69 days after …展开更多
The stability of calcium oxalate is critical for the removal of sodium oxalate from sodium aluminate solutions.This studyinvestigated the behavior of calcium oxalate in sodium aluminate solution containing sodium carb...The stability of calcium oxalate is critical for the removal of sodium oxalate from sodium aluminate solutions.This studyinvestigated the behavior of calcium oxalate in sodium aluminate solution containing sodium carbonate.Results show that calciumoxalate can be converted to tricalcium aluminate hydrate(TCA)and calcium carbonate in sodium aluminate solution and sodiumcarbonate solution,respectively.Elevating temperature,extending residence time,or increasing caustic soda concentration enhancesthe conversion ratio of calcium oxalate in sodium aluminate solution;as a consequence,anti-causticisation occurs.Stability ofcalcium-containing compounds in sodium aluminate solution containing sodium carbonate differs from that in sodium aluminatesolution or sodium carbonate solution.Na2CO3in aluminate solution accelerates the transformation of calcium oxalate;thus,aluminais lost because of4CaO·Al2O3·CO2·11H2O and TCA formation.Calcium carbonate,4CaO·Al2O3·CO2·11H2O and calcium oxalatecan change into TCA in sodium aluminate solution at elevated temperature.Calcium oxalate remains relatively stable in dilutealuminate solution within a short residence time at low temperature.Thus,a novel process for removal of sodium oxalate by limecausticisation was presented and employed in an alumina refinery in China.展开更多
It is known that activated N-methyl-D-aspartate receptors (NMDARs) are a major route of ex-cessive calcium ion (Ca2+) entry in central neu-rons, which may activate degradative processes and thereby cause cell death. T...It is known that activated N-methyl-D-aspartate receptors (NMDARs) are a major route of ex-cessive calcium ion (Ca2+) entry in central neu-rons, which may activate degradative processes and thereby cause cell death. Therefore, NMD- ARs are now recognized to play a key role in the development of many diseases associated with injuries to the central nervous system (CNS). However, it remains a mystery how NMDAR ac-tivity is recruited in the cellular processes leading to excitotoxicity and how NMDAR activ-ity can be controlled at a physiological level. The sodium ion (Na+) is the major cation in ex-tracellular space. With its entry into the cell, Na+ can act as a critical intracellular second mes-senger that regulates many cellular functions. Recent data have shown that intracellular Na+ can be an important signaling factor underlying the up-regulation of NMDARs. While Ca2+ influx during the activation of NMDARs down-regu-lates NMDAR activity, Na+ influx provides an essential positive feedback mechanism to over- come Ca2+-induced inhibition and thereby po-tentiate both NMDAR activity and inward Ca2+ flow. Extensive investigations have been con-ducted to clarify mechanisms underlying Ca2+- mediated signaling. This review focuses on the roles of Na+ in the regulation of Ca2+-mediated NMDAR signaling and toxicity.展开更多
Barium, calcium, sodium, cyanide, phosphate and sulphate and contents of groundwater in Boji-Boji (BB) area and suburbs of Ika land, Delta State, Nigeria were studied. Groundwater is the predominant source of water fo...Barium, calcium, sodium, cyanide, phosphate and sulphate and contents of groundwater in Boji-Boji (BB) area and suburbs of Ika land, Delta State, Nigeria were studied. Groundwater is the predominant source of water for inhabitants of these communities without any form of treatment. 55 borehole water sites spread within these five sample sub-areas. The metal ions were analyzed using Solar Unicam flame Atomic Absorption Spectrophotometer. Sulphate, phosphate, and cyanide contents were determined by colorimetric method. Results indicate the presence of sodium, calcium, sulphate, and phosphate. However, barium and cyanide were below detection limit. Secondly, there was a relatively higher proportion of calcium and sulphate than sodium and phosphate in its aquifer. Thirdly, a mean ratio value of 0.018 and 0.158 was observed for the ratios of Na+/Ca2+ and ?respectively. Fourthly, sodium showed good correlation with all the other parameters. Finally, nearly all the studied parameters have concentrations below the maximum contaminant levels of the World Health Organization (WHO), invariably inferring that the water is wholesome with respect to the analytes. However, concern still remains from a health point of view on the sodium concentrations in many sample areas.展开更多
Hollow calcium carbonate ( CaCO3 ) microspheres were prepared in aqueous solution with the presence of polyoxyethylene (20) sorbitan monolaurate ( Tween20 ) and sodium dodecyl sulfate (SDS). The microspheres w...Hollow calcium carbonate ( CaCO3 ) microspheres were prepared in aqueous solution with the presence of polyoxyethylene (20) sorbitan monolaurate ( Tween20 ) and sodium dodecyl sulfate (SDS). The microspheres were characterized with X-ray diffraction (XRD) , scanning electron microscopy (SEM) and transmission electron microscope (TEM). The X-ray diffraction data showed that the hollow CaCO3 microsphere consisted of calcite crystals. The influence of Tween20 and SDS concentrations on the morphology of CaCO3 crystals was investigated. The results suggested that the "core-shell model" of Tween20/SDS micelle aggregated as templates, which could control the growth of hollow CaCO3 microspheres. The interaction between mixed surfactants and calcium ions played a critical role in organizing calcium carbonate in microscopic level.展开更多
The objective of this study is to present a simple method of statistical calculation that allowed us to determine the relationship between the different data obtained from the characterization of the synthetic carbona...The objective of this study is to present a simple method of statistical calculation that allowed us to determine the relationship between the different data obtained from the characterization of the synthetic carbonated apatites containing sodium, in order to find the fundamental substitution mechanism(s) for incorporation of Na+ and?CO32- and to establish the general formula. For that, a series of hydroxyapatites containing carbonate and sodium (Na-CO3HAps) has been obtained by the precipitation method. All the compounds were characterized by infrared spectra (IR), powder X-ray diffraction (PXRD) and elemental analysis. The statistical treatment of the experiment result allows us to determine the relationship between one variable and the change in the other and to found the fundamental substitution mechanism(s) for incorporation of Na+ and?CO32- . Analysis of variance (ANOVA) allows us to test the models proposed.展开更多
The inhibition and its mechanism of sodium tripolyphosphate (STP) composited with super plasticizers (SPs) on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-r...The inhibition and its mechanism of sodium tripolyphosphate (STP) composited with super plasticizers (SPs) on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electronic probe micro analysis (EPMA), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC) measurements. The experimental results show that compared with STP addition, compositing STP with polycarboxylate (PC) plasticizer, the final setting time is prolonged from 0.5h to 2hs. While formulating STP with naphthalene-based plasticizer (NAP) or sulfonate melamine formaldehyde plasticizer (SMF), the final setting time is reduced to quarter of an hour. Similar changes can also be found in the rate of exothermic hydration and hydration degree. Formulating STP with suitable addition of PC can enhance the strength, while compositing STP and NAP or SMF weakens the strength. Besides, adding STP or STP and SMF, obvious movement (more than 1ev) of binding energy of Ca2p1/2 and Ca2p3/2 is detected. Compared with STP addition, content of the characteristic element (P) of STP is cut down form 1.1% to 0.49% by compositing STP with SMF. Furthermore, as hydration age increases, hydration inhibition in the presence of admixtures weakens and even disappears within 56 h.展开更多
According to the principle of mass balances and thermodynamic data, lg [Me]—pH diagrams (Me=Ca, Mo) for Ca-Mo-CO3-H2O system at 25 ℃ were presented with total dissolved carbon-containing ions concentrations of 0.01 ...According to the principle of mass balances and thermodynamic data, lg [Me]—pH diagrams (Me=Ca, Mo) for Ca-Mo-CO3-H2O system at 25 ℃ were presented with total dissolved carbon-containing ions concentrations of 0.01 mol/L and 1 mol/L, and lg [Me]—pH diagram for Ca-Mo-H2O system at 25 ℃ was also depicted. The effects of system pH value and total dissolved carbon-containing ions concentrations on the concentrations of the species in Ca-Mo-CO3-H2O system were studied. The results show that the stability region of CaMoO4 reduces significantly in the presence of sodium carbonate. In order to achieve effective leaching of molybdenum from CaMoO4, a certain concentration of sodium carbonate is necessary. High total dissolved carbon-containing ions concentrations and high pH values facilitate to the leaching of CaMoO4 and dissolved sodium carbonate is an efficient leaching agent for decomposing CaMoO4.展开更多
A fast and direct method for determination of milk adulteration by monitoring of calcium and sodium concentrations variations was described. Milk samples were furnished by a dairy company located at S?o Carlos (S?o Pa...A fast and direct method for determination of milk adulteration by monitoring of calcium and sodium concentrations variations was described. Milk samples were furnished by a dairy company located at S?o Carlos (S?o Paulo State, Brazil) and and spiked with tap-water, whey, hydrogen peroxide, synthetic urine, urea and synthetic milk in the ranged from 5% to 50% (v/v), expect for caustic soda. Caustic soda was added in the milk until establish the original pH. The milk samples were analyzed by using flame atomic absorption spectrometry (FAAS) and no acid digestion process was required. Results showed a significant decrease in the Na and Ca concentrations with addition of synthetic milk and tap-water, a nonlinear variation with addition of synthetic urine, whey and hydrogen peroxide and a largest increase in the Na concentration with addition of NaOH. Correlation between Na and Ca concentrations in pure and adulterated milk were evaluated by paired t-test at a 95% confidence level. Results showed that the method proposed is efficient to identify samples adulterated with tap-water, caustic soda, synthetics milk and urine.展开更多
The calcium binding of erythrocyte membrane was determined in spontaneous hypertensiverats (SHR)and renovascular hypertensive rats (RVHR two-kidney, one-clip model) and the effect ofsodium tanshinone Ⅱ-A sulfonate(DS...The calcium binding of erythrocyte membrane was determined in spontaneous hypertensiverats (SHR)and renovascular hypertensive rats (RVHR two-kidney, one-clip model) and the effect ofsodium tanshinone Ⅱ-A sulfonate(DS-201)on the calcium binding in SHRs was investigated. Ourresults show that the basal calcium binding was reduced in SHRs (P<0.01 vs WKY),while the maximalcalcium binding was not,but both typies calcium bindings had no significant change in RVHRs.Sodiumtanshinone Ⅱ-A sulfonate (125μ mol/L)have no effect on the calcium binding of ecythrocyte membraneof SHR in vitro.These data further support the hypothesis that there is a cell membrane abnormalitypresent in SHRs which may possibly serve as a marker genetics of in hypertension.展开更多
AIM: To compare the effect of calcium and cholecalciferol alone and along with additional sodium fluoride or ibandronate on bone mineral density (BMD) and fractures in patients with Crohn's disease (CD). METHODS: ...AIM: To compare the effect of calcium and cholecalciferol alone and along with additional sodium fluoride or ibandronate on bone mineral density (BMD) and fractures in patients with Crohn's disease (CD). METHODS: Patients (n =148) with reduced BMD (T-score < -1) were randomized to receive cholecalciferol (1000 IU) and calcium citrate (800 mg) daily alone(group A, n = 32) or along with additional sodium fluoride (25 mg bid) (group B, n = 62) or additional ibandronate (1 mg iv/3-monthly) (group C, n = 54). Dual energy X-ray absorptiometry of the lumbar spine (L1-L4) and proximal right femur and X-rays of the spine were performed at baseline and after 1.0, 2.25 and 3.5 years. Fracture-assessment included visual reading of X-rays and quantitative morphometry of vertebral bodies (T4-L4).RESULTS: One hundred and twenty three (83.1%) patients completed the first year for intention-to-treat (ITT) analysis. Ninety two (62.2%) patients completed the second year and 71 (47.8%) the third year available for per-protocol (PP) analysis. With a significant increase in T-score of the lumbar spine by +0.28 ± 0.35 [95% conf idence interval (CI): 0.162-0.460, P < 0.01], +0.33 ± 0.49 (95% CI: 0.109-0.558, P < 0.01), +0.43 ± 0.47 (95% CI: 0.147-0.708, P < 0.01) in group A, +0.22 ± 0.33 (95% CI: 0.125-0.321, P < 0.01); +0.47 ± 0.60 (95% CI: 0.262-0.676, P < 0.01), +0.51 ± 0.44 (95% CI: 0.338-0.682, P < 0.01) in group B and +0.22 ± 0.38 (95% CI: 0.111-0.329, P < 0.01), +0.36 ± 0.53 (95% CI: 0.147-0.578, P < 0.01), +0.41 ± 0.48 (95% CI: 0.238-0.576, P < 0.01) in group C, respectively, during the 1.0, 2.25 and 3.5 year periods (PP analysis), no treatment regimen was superior in any in- or between-group analyses. In the ITT analysis, similar results in all in- and between-group analyses with a significant in-group but non-significant between-group increase in T-score of the lumbar spine by 0.38 ± 0.46 (group A, P < 0.01), 0.37 ± 0.50 (group B, P < 0.01) and 0.35 ± 0.49 (group C, P < 0.01) was observed. Follow-up in ITT analysis was still 2.65 years. One vertebral fracture in the sodium fluoride group was detected. Study medication was safe and well tolerated. CONCLUSION: Additional sodium fluoride or ibandronate had no benefit over calcium and cholecalciferol alone in managing reduced BMD in CD.展开更多
Thin calcium phosphate catings on titanium alloy substrates were prepared by Ar^+ ion beam assisted deposition(IBAD) from hydroxyl-poly-calcium sodium phosphate(HPPA) target.The coatings were analyzed by XRD,FTIR,XPS,...Thin calcium phosphate catings on titanium alloy substrates were prepared by Ar^+ ion beam assisted deposition(IBAD) from hydroxyl-poly-calcium sodium phosphate(HPPA) target.The coatings were analyzed by XRD,FTIR,XPS,These analyses revealed that the as-deposited films were amorphous or no apparent crystallinity.No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were presented for CO3^-2,The calcium to phosphorous ratio of these catings in different IBAD conditions varied from 0.46 to 3.36.展开更多
This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na<sub>2</sub>...This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na<sub>2</sub>CO<sub>3</sub>): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.展开更多
Temperature affects the flotation of quartz in the calcium/sodium oleate(Na OL)system,while there is a lack of understanding of its potential mechanism.Therefore,in this work,the flotation response of quartz to temper...Temperature affects the flotation of quartz in the calcium/sodium oleate(Na OL)system,while there is a lack of understanding of its potential mechanism.Therefore,in this work,the flotation response of quartz to temperature was investigated via micro-flotation experiments,interface property analyses,and theoretical calculations.Flotation results demonstrated that increasing temperature contributed to higher flotation recovery of quartz,which enhanced the removal of quartz from hematite.Surface tension results revealed that higher temperatures lowered the critical micelle concentration(CMC)and surface tension of the Na OL solution,and thus enhanced its surface activity.Solution chemistry calculations and X-ray photoelectron spectroscopy(XPS)measurements confirmed that the increased content of Ca(OH)+achieved by increasing temperatures enhanced the adsorption amounts of calcium species(acting as activation sites)on the quartz surface.Dynamic light scattering(DLS)measurements verified that the association degree of RCOOàto form(RCOO)22àwas strengthened.Furthermore,adsorption density measurements and molecular dynamics(MD)simulations confirmed that increasing the temperature facilitated Na OL adsorption toward the surface of the quartz,which was attributed to the stronger interaction between Na OL and the calcium-activated quartz surface at higher temperatures.As a result,quartz flotation was improved by increasing temperatures.Accordingly,a possible adsorption model was proposed.展开更多
A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium c...A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR.展开更多
The mineral transition and formation mechanism of calcium aluminate compounds in CaO-Al2O3-Na2O system during the hightemperature sintering process were systematically investigated using DSC-TG,XRD,SEM-EDS,FTIR,and Ra...The mineral transition and formation mechanism of calcium aluminate compounds in CaO-Al2O3-Na2O system during the hightemperature sintering process were systematically investigated using DSC-TG,XRD,SEM-EDS,FTIR,and Raman spectra,and the crystal structure of Na4Ca3(AlO2)10 was also simulated by Material Studio software.The results indicated that the minerals formed during the sintering process included Na4Ca3(AlO2)10,CaO·Al2O3,and 12 CaO·7 Al2O3,and the content of Na4Ca3(AlO2)10 could reach 92 wt%when sintered at 1200°C for 30 min.The main formation stage of Na4Ca3(AlO2)10 occurred at temperatures from 970 to 1100°C,and the content could reach82 wt%when the reaction temperature increased to 1100°C.The crystal system of Na4Ca3(AlO2)10 was tetragonal,and the cells preferred to grow along crystal planes(110)and(210).The formation of Na4Ca3(AlO2)10 was an exothermic reaction that followed a secondary reaction model,and its activation energy was 223.97 kJ/mol.展开更多
The purpose of this work is to find a new way for utilizing the rich sodium sulfate resource to produce soda ash. A novel process is proposed which uses aqueous dichromate solution as working medium through decomposit...The purpose of this work is to find a new way for utilizing the rich sodium sulfate resource to produce soda ash. A novel process is proposed which uses aqueous dichromate solution as working medium through decomposition of calcium carbonate in aqueous sodium dichromate, complex decomposition of aqueous sodium sulfate and calcium chromate, regeneration of sodium dichromate and production of sodium bicarbonate from carbonation of aqueous sodium chromate solution, processing and utilization of byproduct calcium sulfate, and production of sodium carbonate from sodium bicarbonate. The process has the features of less corrosion and pollution and low energy consumption.展开更多
Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phos...Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phosphoric acid (TF112) as a collector and sodium hexametaphosphate (SH) as a regulator.展开更多
The object of this study is to investigate the effects of sodium alginate(SA)and CaCl_(2) on the physicochemical characteristics of shrimp surimi by studying gel strength,water holding capacity(WHC),as well as by text...The object of this study is to investigate the effects of sodium alginate(SA)and CaCl_(2) on the physicochemical characteristics of shrimp surimi by studying gel strength,water holding capacity(WHC),as well as by texture profile analysis(TPA).In addition,the mechanism was analyzed through chemical interactions,protein secondary structure,and microstructure.The results showed that with the addition of different concentrations of SA and CaCl_(2) to the shrimp surimi,the gel quality firstly increased and then decreased with the increase of SA and CaCl_(2) concentrations.The highest values of WHC,breaking force and gel strength were obtained with the addition of 1.2%SA or 0.1%CaCl_(2).When SA and CaCl_(2) were used in concert,the group containing 1.2%SA and 0.15%CaCl_(2) had the highest gel strength with the densest three-dimensional network structure of the gel.In addition,the results of chemical interaction analyses showed that hydrogen and ionic bonds were the main chemical bonds of shrimp surimi sol,while shrimp surimi gel mainly consisted of hydrophobic and disulfide bonds.The incorporation of SA and CaCl_(2) resulted in a significant increase in hydrophobic interactions and disulfide bonding,which could effectively improve the gel properties of shrimp surimi.展开更多
基金Supported by Agricultural Environment and Ecosystem Protection Program of Ministry of Agriculture of the People's Republic of China(2110402-201258)Agricultural Science and Technology Achievement Transformation and Promotion Program of Tianjin City(201203030)Cooperation Project of China and Canada(IPNI,Tianjin-2011)~~
文摘ObjectiveThis study aimed to investigate the effect of the interactions among potassium (K), calcium (Ca) and sodium (Na) on cabbage growth and nutrient absorption. MethodA total of 11 treatments with different levels of K, Ca and Na were set in the pot experiment to measure the nutrient content and uptake in cabbage plants. ResultThe use of K or the combined use of K and Ca improved the cabbage absorption on K and Ca. In addition, K and Ca presented an interaction as that appropriate amount of Ca promoted K uptake while excessive Ca inhibited the uptake. The treatment of Ca 2 K 3 with 0.33 g/pot of Ca and 0.67 g/pot of K could significantly increase the quantity of dry matter accumulation and absorption of Ca and K in cabbage, was the best among all treatments. ConclusionApplication of suitable amount of Ca could release the Na stress on cabbage growth at the low level of Na in soil.
文摘A field experiment was conducted on a sandy loam soil at an Experimental Farm in Taejon, South Korea, to determine the effects of paper mill sludge compost application rates on K, Na, Ca and Mg concentrations of soybean (Glycine max (L.) Merr.) aboveground tissues and the genotypic effects on the concentrations of these elements. Sludge compost treatments of 0, 75, and 150 t ha-1 were applied to 30 diverse soybean cultivars. Concentrations of K, Na, Ca, and Mg in aboveground tissues harvested 69 days after …
基金Project(51274242) supported by the National Natural Science Foundation of ChinaProject(2015CX001) supported by the Innovation-driven Plan of Central South University,China
文摘The stability of calcium oxalate is critical for the removal of sodium oxalate from sodium aluminate solutions.This studyinvestigated the behavior of calcium oxalate in sodium aluminate solution containing sodium carbonate.Results show that calciumoxalate can be converted to tricalcium aluminate hydrate(TCA)and calcium carbonate in sodium aluminate solution and sodiumcarbonate solution,respectively.Elevating temperature,extending residence time,or increasing caustic soda concentration enhancesthe conversion ratio of calcium oxalate in sodium aluminate solution;as a consequence,anti-causticisation occurs.Stability ofcalcium-containing compounds in sodium aluminate solution containing sodium carbonate differs from that in sodium aluminatesolution or sodium carbonate solution.Na2CO3in aluminate solution accelerates the transformation of calcium oxalate;thus,aluminais lost because of4CaO·Al2O3·CO2·11H2O and TCA formation.Calcium carbonate,4CaO·Al2O3·CO2·11H2O and calcium oxalatecan change into TCA in sodium aluminate solution at elevated temperature.Calcium oxalate remains relatively stable in dilutealuminate solution within a short residence time at low temperature.Thus,a novel process for removal of sodium oxalate by limecausticisation was presented and employed in an alumina refinery in China.
文摘It is known that activated N-methyl-D-aspartate receptors (NMDARs) are a major route of ex-cessive calcium ion (Ca2+) entry in central neu-rons, which may activate degradative processes and thereby cause cell death. Therefore, NMD- ARs are now recognized to play a key role in the development of many diseases associated with injuries to the central nervous system (CNS). However, it remains a mystery how NMDAR ac-tivity is recruited in the cellular processes leading to excitotoxicity and how NMDAR activ-ity can be controlled at a physiological level. The sodium ion (Na+) is the major cation in ex-tracellular space. With its entry into the cell, Na+ can act as a critical intracellular second mes-senger that regulates many cellular functions. Recent data have shown that intracellular Na+ can be an important signaling factor underlying the up-regulation of NMDARs. While Ca2+ influx during the activation of NMDARs down-regu-lates NMDAR activity, Na+ influx provides an essential positive feedback mechanism to over- come Ca2+-induced inhibition and thereby po-tentiate both NMDAR activity and inward Ca2+ flow. Extensive investigations have been con-ducted to clarify mechanisms underlying Ca2+- mediated signaling. This review focuses on the roles of Na+ in the regulation of Ca2+-mediated NMDAR signaling and toxicity.
文摘Barium, calcium, sodium, cyanide, phosphate and sulphate and contents of groundwater in Boji-Boji (BB) area and suburbs of Ika land, Delta State, Nigeria were studied. Groundwater is the predominant source of water for inhabitants of these communities without any form of treatment. 55 borehole water sites spread within these five sample sub-areas. The metal ions were analyzed using Solar Unicam flame Atomic Absorption Spectrophotometer. Sulphate, phosphate, and cyanide contents were determined by colorimetric method. Results indicate the presence of sodium, calcium, sulphate, and phosphate. However, barium and cyanide were below detection limit. Secondly, there was a relatively higher proportion of calcium and sulphate than sodium and phosphate in its aquifer. Thirdly, a mean ratio value of 0.018 and 0.158 was observed for the ratios of Na+/Ca2+ and ?respectively. Fourthly, sodium showed good correlation with all the other parameters. Finally, nearly all the studied parameters have concentrations below the maximum contaminant levels of the World Health Organization (WHO), invariably inferring that the water is wholesome with respect to the analytes. However, concern still remains from a health point of view on the sodium concentrations in many sample areas.
基金Supported by the Beijing Natural Science Foundation(2082021)the National Science & Technology Pillar Program in the 12th Five-Year Plan Period (2011BAE06B06-2)
文摘Hollow calcium carbonate ( CaCO3 ) microspheres were prepared in aqueous solution with the presence of polyoxyethylene (20) sorbitan monolaurate ( Tween20 ) and sodium dodecyl sulfate (SDS). The microspheres were characterized with X-ray diffraction (XRD) , scanning electron microscopy (SEM) and transmission electron microscope (TEM). The X-ray diffraction data showed that the hollow CaCO3 microsphere consisted of calcite crystals. The influence of Tween20 and SDS concentrations on the morphology of CaCO3 crystals was investigated. The results suggested that the "core-shell model" of Tween20/SDS micelle aggregated as templates, which could control the growth of hollow CaCO3 microspheres. The interaction between mixed surfactants and calcium ions played a critical role in organizing calcium carbonate in microscopic level.
文摘The objective of this study is to present a simple method of statistical calculation that allowed us to determine the relationship between the different data obtained from the characterization of the synthetic carbonated apatites containing sodium, in order to find the fundamental substitution mechanism(s) for incorporation of Na+ and?CO32- and to establish the general formula. For that, a series of hydroxyapatites containing carbonate and sodium (Na-CO3HAps) has been obtained by the precipitation method. All the compounds were characterized by infrared spectra (IR), powder X-ray diffraction (PXRD) and elemental analysis. The statistical treatment of the experiment result allows us to determine the relationship between one variable and the change in the other and to found the fundamental substitution mechanism(s) for incorporation of Na+ and?CO32- . Analysis of variance (ANOVA) allows us to test the models proposed.
基金Funded by the Major State Basic Research Development Program of China (973 Program) (No. 2009CB623104)the National Technology R&D Program for the 11th Five-year Plan (No. 2006BAJ05B03)
文摘The inhibition and its mechanism of sodium tripolyphosphate (STP) composited with super plasticizers (SPs) on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electronic probe micro analysis (EPMA), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC) measurements. The experimental results show that compared with STP addition, compositing STP with polycarboxylate (PC) plasticizer, the final setting time is prolonged from 0.5h to 2hs. While formulating STP with naphthalene-based plasticizer (NAP) or sulfonate melamine formaldehyde plasticizer (SMF), the final setting time is reduced to quarter of an hour. Similar changes can also be found in the rate of exothermic hydration and hydration degree. Formulating STP with suitable addition of PC can enhance the strength, while compositing STP and NAP or SMF weakens the strength. Besides, adding STP or STP and SMF, obvious movement (more than 1ev) of binding energy of Ca2p1/2 and Ca2p3/2 is detected. Compared with STP addition, content of the characteristic element (P) of STP is cut down form 1.1% to 0.49% by compositing STP with SMF. Furthermore, as hydration age increases, hydration inhibition in the presence of admixtures weakens and even disappears within 56 h.
基金Project(50434010) supported by the National Natural Science Foundation of China
文摘According to the principle of mass balances and thermodynamic data, lg [Me]—pH diagrams (Me=Ca, Mo) for Ca-Mo-CO3-H2O system at 25 ℃ were presented with total dissolved carbon-containing ions concentrations of 0.01 mol/L and 1 mol/L, and lg [Me]—pH diagram for Ca-Mo-H2O system at 25 ℃ was also depicted. The effects of system pH value and total dissolved carbon-containing ions concentrations on the concentrations of the species in Ca-Mo-CO3-H2O system were studied. The results show that the stability region of CaMoO4 reduces significantly in the presence of sodium carbonate. In order to achieve effective leaching of molybdenum from CaMoO4, a certain concentration of sodium carbonate is necessary. High total dissolved carbon-containing ions concentrations and high pH values facilitate to the leaching of CaMoO4 and dissolved sodium carbonate is an efficient leaching agent for decomposing CaMoO4.
基金The authors are grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),Min-istério da Agricultura,Pecuária e Abastecimento(MAPA) Fundacao de AmparoàPesquisa do Estado de Sao Paulo-FAPESP(processes number 2009/01345-6 and 2009/10541-3)for the financial support.
文摘A fast and direct method for determination of milk adulteration by monitoring of calcium and sodium concentrations variations was described. Milk samples were furnished by a dairy company located at S?o Carlos (S?o Paulo State, Brazil) and and spiked with tap-water, whey, hydrogen peroxide, synthetic urine, urea and synthetic milk in the ranged from 5% to 50% (v/v), expect for caustic soda. Caustic soda was added in the milk until establish the original pH. The milk samples were analyzed by using flame atomic absorption spectrometry (FAAS) and no acid digestion process was required. Results showed a significant decrease in the Na and Ca concentrations with addition of synthetic milk and tap-water, a nonlinear variation with addition of synthetic urine, whey and hydrogen peroxide and a largest increase in the Na concentration with addition of NaOH. Correlation between Na and Ca concentrations in pure and adulterated milk were evaluated by paired t-test at a 95% confidence level. Results showed that the method proposed is efficient to identify samples adulterated with tap-water, caustic soda, synthetics milk and urine.
文摘The calcium binding of erythrocyte membrane was determined in spontaneous hypertensiverats (SHR)and renovascular hypertensive rats (RVHR two-kidney, one-clip model) and the effect ofsodium tanshinone Ⅱ-A sulfonate(DS-201)on the calcium binding in SHRs was investigated. Ourresults show that the basal calcium binding was reduced in SHRs (P<0.01 vs WKY),while the maximalcalcium binding was not,but both typies calcium bindings had no significant change in RVHRs.Sodiumtanshinone Ⅱ-A sulfonate (125μ mol/L)have no effect on the calcium binding of ecythrocyte membraneof SHR in vitro.These data further support the hypothesis that there is a cell membrane abnormalitypresent in SHRs which may possibly serve as a marker genetics of in hypertension.
文摘AIM: To compare the effect of calcium and cholecalciferol alone and along with additional sodium fluoride or ibandronate on bone mineral density (BMD) and fractures in patients with Crohn's disease (CD). METHODS: Patients (n =148) with reduced BMD (T-score < -1) were randomized to receive cholecalciferol (1000 IU) and calcium citrate (800 mg) daily alone(group A, n = 32) or along with additional sodium fluoride (25 mg bid) (group B, n = 62) or additional ibandronate (1 mg iv/3-monthly) (group C, n = 54). Dual energy X-ray absorptiometry of the lumbar spine (L1-L4) and proximal right femur and X-rays of the spine were performed at baseline and after 1.0, 2.25 and 3.5 years. Fracture-assessment included visual reading of X-rays and quantitative morphometry of vertebral bodies (T4-L4).RESULTS: One hundred and twenty three (83.1%) patients completed the first year for intention-to-treat (ITT) analysis. Ninety two (62.2%) patients completed the second year and 71 (47.8%) the third year available for per-protocol (PP) analysis. With a significant increase in T-score of the lumbar spine by +0.28 ± 0.35 [95% conf idence interval (CI): 0.162-0.460, P < 0.01], +0.33 ± 0.49 (95% CI: 0.109-0.558, P < 0.01), +0.43 ± 0.47 (95% CI: 0.147-0.708, P < 0.01) in group A, +0.22 ± 0.33 (95% CI: 0.125-0.321, P < 0.01); +0.47 ± 0.60 (95% CI: 0.262-0.676, P < 0.01), +0.51 ± 0.44 (95% CI: 0.338-0.682, P < 0.01) in group B and +0.22 ± 0.38 (95% CI: 0.111-0.329, P < 0.01), +0.36 ± 0.53 (95% CI: 0.147-0.578, P < 0.01), +0.41 ± 0.48 (95% CI: 0.238-0.576, P < 0.01) in group C, respectively, during the 1.0, 2.25 and 3.5 year periods (PP analysis), no treatment regimen was superior in any in- or between-group analyses. In the ITT analysis, similar results in all in- and between-group analyses with a significant in-group but non-significant between-group increase in T-score of the lumbar spine by 0.38 ± 0.46 (group A, P < 0.01), 0.37 ± 0.50 (group B, P < 0.01) and 0.35 ± 0.49 (group C, P < 0.01) was observed. Follow-up in ITT analysis was still 2.65 years. One vertebral fracture in the sodium fluoride group was detected. Study medication was safe and well tolerated. CONCLUSION: Additional sodium fluoride or ibandronate had no benefit over calcium and cholecalciferol alone in managing reduced BMD in CD.
基金Contract grant sponsor:Key Laboratory of Radiation Physics and Technology of Education Ministry (No.2000-03)
文摘Thin calcium phosphate catings on titanium alloy substrates were prepared by Ar^+ ion beam assisted deposition(IBAD) from hydroxyl-poly-calcium sodium phosphate(HPPA) target.The coatings were analyzed by XRD,FTIR,XPS,These analyses revealed that the as-deposited films were amorphous or no apparent crystallinity.No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were presented for CO3^-2,The calcium to phosphorous ratio of these catings in different IBAD conditions varied from 0.46 to 3.36.
文摘This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na<sub>2</sub>CO<sub>3</sub>): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.
基金supported by the Natio nal Natu ral Science Foundation of China(Nos.5187407251974064+1 种基金52174239)the Fundamental Research Funds for the Central Universities(No.N2101025)。
文摘Temperature affects the flotation of quartz in the calcium/sodium oleate(Na OL)system,while there is a lack of understanding of its potential mechanism.Therefore,in this work,the flotation response of quartz to temperature was investigated via micro-flotation experiments,interface property analyses,and theoretical calculations.Flotation results demonstrated that increasing temperature contributed to higher flotation recovery of quartz,which enhanced the removal of quartz from hematite.Surface tension results revealed that higher temperatures lowered the critical micelle concentration(CMC)and surface tension of the Na OL solution,and thus enhanced its surface activity.Solution chemistry calculations and X-ray photoelectron spectroscopy(XPS)measurements confirmed that the increased content of Ca(OH)+achieved by increasing temperatures enhanced the adsorption amounts of calcium species(acting as activation sites)on the quartz surface.Dynamic light scattering(DLS)measurements verified that the association degree of RCOOàto form(RCOO)22àwas strengthened.Furthermore,adsorption density measurements and molecular dynamics(MD)simulations confirmed that increasing the temperature facilitated Na OL adsorption toward the surface of the quartz,which was attributed to the stronger interaction between Na OL and the calcium-activated quartz surface at higher temperatures.As a result,quartz flotation was improved by increasing temperatures.Accordingly,a possible adsorption model was proposed.
基金Project(51274242)supported by the National Natural Science Foundation of ChinaProject(2015CX001)supported by the Innovation-driven Plan of Central South University,China
文摘A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR.
基金financially supported by the National Key R&D Program of China(No.2018YFC1901903)the National Nature Science Foundation of China(Nos.51674075 and 51774079)the Fundamental Research Funds for the Central Universities,China(No.N182508026)。
文摘The mineral transition and formation mechanism of calcium aluminate compounds in CaO-Al2O3-Na2O system during the hightemperature sintering process were systematically investigated using DSC-TG,XRD,SEM-EDS,FTIR,and Raman spectra,and the crystal structure of Na4Ca3(AlO2)10 was also simulated by Material Studio software.The results indicated that the minerals formed during the sintering process included Na4Ca3(AlO2)10,CaO·Al2O3,and 12 CaO·7 Al2O3,and the content of Na4Ca3(AlO2)10 could reach 92 wt%when sintered at 1200°C for 30 min.The main formation stage of Na4Ca3(AlO2)10 occurred at temperatures from 970 to 1100°C,and the content could reach82 wt%when the reaction temperature increased to 1100°C.The crystal system of Na4Ca3(AlO2)10 was tetragonal,and the cells preferred to grow along crystal planes(110)and(210).The formation of Na4Ca3(AlO2)10 was an exothermic reaction that followed a secondary reaction model,and its activation energy was 223.97 kJ/mol.
基金Supported by the National Natural Science Foundation of China (No. 50234040) the High-Technology Research and Development Program of China (No. 2001AA6407010).
文摘The purpose of this work is to find a new way for utilizing the rich sodium sulfate resource to produce soda ash. A novel process is proposed which uses aqueous dichromate solution as working medium through decomposition of calcium carbonate in aqueous sodium dichromate, complex decomposition of aqueous sodium sulfate and calcium chromate, regeneration of sodium dichromate and production of sodium bicarbonate from carbonation of aqueous sodium chromate solution, processing and utilization of byproduct calcium sulfate, and production of sodium carbonate from sodium bicarbonate. The process has the features of less corrosion and pollution and low energy consumption.
文摘Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phosphoric acid (TF112) as a collector and sodium hexametaphosphate (SH) as a regulator.
基金supported by the Public Welfare Project of Ningbo(No.2022S211)the National Key R&D Program of China(No.2020YFD0900903)。
文摘The object of this study is to investigate the effects of sodium alginate(SA)and CaCl_(2) on the physicochemical characteristics of shrimp surimi by studying gel strength,water holding capacity(WHC),as well as by texture profile analysis(TPA).In addition,the mechanism was analyzed through chemical interactions,protein secondary structure,and microstructure.The results showed that with the addition of different concentrations of SA and CaCl_(2) to the shrimp surimi,the gel quality firstly increased and then decreased with the increase of SA and CaCl_(2) concentrations.The highest values of WHC,breaking force and gel strength were obtained with the addition of 1.2%SA or 0.1%CaCl_(2).When SA and CaCl_(2) were used in concert,the group containing 1.2%SA and 0.15%CaCl_(2) had the highest gel strength with the densest three-dimensional network structure of the gel.In addition,the results of chemical interaction analyses showed that hydrogen and ionic bonds were the main chemical bonds of shrimp surimi sol,while shrimp surimi gel mainly consisted of hydrophobic and disulfide bonds.The incorporation of SA and CaCl_(2) resulted in a significant increase in hydrophobic interactions and disulfide bonding,which could effectively improve the gel properties of shrimp surimi.