NECAB family of neuronal calcium-binding proteins in health and disease

The N-terminal EF-hand calcium-binding proteins 1–3(NECAB1–3) constitute a family of predominantly neuronal proteins characterized by the presence of at least one EF-hand calcium-binding domain and a functionally less well characterized C-terminal antibiotic biosynthesis monooxygenase domain. All three family members were initially discovered due to their interactions with other proteins. NECAB1 associates with synaptotagmin-1, a critical neuronal protein involved in membrane trafficking and synaptic vesicle exocytosis. NECAB2 interacts with predominantly striatal G-protein-coupled receptors, while NECAB3 partners with amyloid-β A4 precursor protein-binding family A members 2 and 3, key regulators of amyloid-β production. This demonstrates the capacity of the family for interactions with various classes of proteins. NECAB proteins exhibit distinct subcellular localizations: NECAB1 is found in the nucleus and cytosol, NECAB2 resides in endosomes and the plasma membrane, and NECAB3 is present in the endoplasmic reticulum and Golgi apparatus. The antibiotic biosynthesis monooxygenase domain, an evolutionarily ancient component, is akin to atypical heme oxygenases in prokaryotes but is not wellcharacterized in vertebrates. Prokaryotic antibiotic biosynthesis monooxygenase domains typically form dimers, suggesting that calcium-mediated conformational changes in NECAB proteins may induce antibiotic biosynthesis monooxygenase domain dimerization, potentially activating some enzymatic properties. However, the substrate for this enzymatic activity remains uncertain. Alternatively, calcium-mediated conformational changes might influence protein interactions or the subcellular localization of NECAB proteins by controlling the availability of protein–protein interaction domains situated between the EF hands and the antibiotic biosynthesis monooxygenase domain. This review summarizes what is known about genomic organization, tissue expression, intracellular localization, interaction partners, and the physiological and pathophysiological role of the NECAB family.

Preparation and applications of calcium ferrite as a functional material:A review

Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,environmental engineering,and biomedicine.There-fore,the obtained research results need to be systematically summarized,and new perspectives on CF and its composite materials need to be analyzed.Based on the presented studies of CF and its composite materials,the types and structures of the crystal are summarized.In addition,the current application technologies and theoretical mechanisms with various properties in different fields are elucidated.Moreover,the various preparation methods of CF and its composite materials are elaborated in detail.Most importantly,the advantages and disadvantages of the synthesis methods of CF and its composite materials are discussed,and the existing problems and emerging challenges in practical production are identified.Furthermore,the key future research directions of CF and its composite materials have been prospected from the potential application technologies to provide references for its synthesis and efficient utilization.

Potassium and calcium channels in different nerve cells act as therapeutic targets in neurological disorders

The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.

CEA、CA125、CA199对胃癌患者病灶转移的评估价值及与胃癌病理特征的关系

目的探讨癌胚抗原(CEA)、糖类抗原125(CA125)和糖类抗原199(CA199)对胃癌患者病灶转移的评估价值及与胃癌病理特征的关系。方法收集102例胃癌患者临床资料作为观察组,另外收集健康体检者39例作为对照组,比较观察组与对照组的一般资料及血清CEA、CA125、CA199水平。分析血清CEA、CA125、CA199水平与胃癌病理特征的关系。随访患者1年的病灶转移情况,比较转移组与未转移组的CEA、CA125、CA199水平,分析三者对胃癌患者病灶转移的评估价值。结果2组性别、年龄、体质量指数比较差异无统计学意义(P>0.05),观察组CEA、CA125、CA199水平均高于对照组,差异有统计学意义(P<0.05)。胃癌低分化患者CEA、CA125、CA199水平均高于高中分化患者,Ⅲ+Ⅳ期患者CEA、CA125、CA199水平均高于Ⅰ+Ⅱ期患者,差异有统计学意义(P均<0.001)。转移组CEA、CA125、CA199表达水平均高于未转移组,差异有统计学意义(P均<0.001)。CEA、CA125、CA199的预测阈值分别为11.485μg/L、42.580 kU/L、55.055 kU/L。CEA、CA125、CA199对胃癌远处转移预测的曲线下面积(AUC)分别为0.771、0.784、0.731,三者联合预测价值较高,AUC面积为0.928,灵敏度、特异度较高。结论低分化、Ⅲ+Ⅳ期、远处转移患者CEA、CA125、CA199水平较高,CEA、CA125、CA199水平与胃癌患者病理分期存在一定关系,三者联合对病灶转移的预测效能较好。

Towards carbon neutrality of calcium carbide-based acetylene production with sustainable biomass resources

Acetylene is produced from the reaction between calcium carbide(CaC_(2))and water,while the production of CaC_(2) generates significant amount of carbon dioxide not only because it is an energy-intensive process but also the raw material for CaC_(2) synthesis is from coal.Here,a comprehensive biomass-to-acetylene process was constructed that integrated several units including biomass pyrolysis,oxygen-thermal CaC_(2) fabrication and calcium looping.For comparison,a coal-to-acetylene process was also established by using coal as feedstock.The carbon efficiency,energy efficiency and environmental impacts of the bio-based calcium carbide acetylene(BCCA)and coal-based calcium carbide acetylene(CCCA)processes were systematically analyzed.Moreover,the environmental impacts were further evaluated by applying thermal integration at system level and energy substitution in CaC_(2) furnace.Even though the BCCA process showed lower carbon efficiency and energy efficiency than that of the CCCA process,life cycle assessment demonstrated the BCCA(1.873 kgCO_(2eq) kg-prod^(-1))a lower carbon footprint process which is 0.366 kgCO_(2eq) kg-prod^(-1) lower compared to the CCCA process.With sustainable energy(biomass power)substitution in CaC_(2) furnace,an even lower GWP value of 1.377 kgCO_(2eq) kg-prod^(-1) can be achieved in BCCA process.This work performed a systematic analysis on integrating biomass into industrial acetylene production,and revealed the positive role of biomass as raw material(carbon)and energy supplier.

Elaidic acid leads to mitochondrial dysfunction via mitochondria-associated membranes triggers disruption of mitochondrial calcium fluxes

Elaidic acid(EA)stimulation can lead to endoplasmic reticulum stress(ERS),accompanied by a large release of Ca^(2+),and ultimately the activation of NLRP3 inflammasome in Kupffer cells(KCs).Mitochondrial instability or dysfunction may be the key stimulating factors to activate NLRP3 inflammasome,and sustained Ca^(2+)transfer can result in mitochondrial dysfunction.We focused on KCs to explore the damage to mitochondria by EA.After EA stimulation,cells produced an oxidative stress(OS)response with a significant increase in ROS release.Immunoprecipitation experiments and the addition of inhibitors revealed that the increase in the level of intracellular Ca^(2+)led to Ca^(2+)accumulation in the mitochondrial matrix via mitochondria-associated membranes(MAMs).This was accompanied by a significant release of m ROS,loss of MMP and ATP,and a significant increase in mitochondrial permeability transition pore opening,ultimately leading to mitochondrial instability.These findings confirmed the mechanism that EA induced mitochondrial Ca^(2+)imbalance in KCs via MAM,ultimately leading to mitochondrial dysfunction.Meanwhile,EA induced OS and the decrease of MMP and ATP in rat liver,and significant lesions were found in liver mitochondria.Swelling of the inner mitochondrial cristae and mitochondrial vacuolization occurred,with a marked increase in lipid droplets.

Biomineralization of soil with crude soybean urease using different calcium salts

Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).

Decreased eggshell strength caused by impairment of uterine calcium transport coincide with higher bone minerals and quality in aged laying hens

Background Deteriorations in eggshell and bone quality are major challenges in aged laying hens.This study compared the differences of eggshell quality,bone parameters and their correlations as well as uterine physiologi-cal characteristics and the bone remodeling processes of hens laying eggs of different eggshell breaking strength to explore the mechanism of eggshell and bone quality reduction and their interaction.A total of 24074-week-old Hy-line Brown laying hens were selected and allocated to a high(HBS,44.83±1.31 N)or low(LBS,24.43±0.57 N)eggshell breaking strength group.Results A decreased thickness,weight and weight ratio of eggshells were observed in the LBS,accompanied with ultrastructural deterioration and total Ca reduction.Bone quality was negatively correlated with eggshell quality,marked with enhanced structures and increased components in the LBS.In the LBS,the mammillary knobs and effective layer grew slowly.At the initiation stage of eggshell calcification,a total of 130 differentially expressed genes(DEGs,122 upregulated and 8 downregulated)were identified in the uterus of hens in the LBS relative to those in the HBS.These DEGs were relevant to apoptosis due to the cellular Ca overload.Higher values of p62 protein level,caspase-8 activity,Bax protein expression and lower values of Bcl protein expression and Bcl/Bax ratio were seen in the LBS.TUNEL assay and hematoxylin-eosin staining showed a significant increase in TUNEL-positive cells and tissue damages in the uterus of the LBS.Although few DEGs were identified at the growth stage,similar uterine tissue damages were also observed in the LBS.The expressions of runt-related transcription factor 2 and osteocal-cin were upregulated in humeri of the LBS.Enlarged diameter and more structural damages of endocortical bones and decreased ash were observed in femurs of the HBS.Conclusion The lower eggshell breaking strength may be attributed to a declined Ca transport due to uterine tissue damages,which could affect eggshell calcification and lead to a weak ultrastructure.Impaired uterine Ca transport may result in reduced femoral bone resorption and increased humeral bone formation to maintain a higher mineral and bone quality in the LBS.

Calmodulins and calmodulin-like proteins-mediated plant organellar calcium signaling networks under abiotic stress

Plant calmodulins(CaMs)and calmodulin-like proteins(CMLs)mediate Ca~(2+)signaling in response to abiotic stresses.Manipulation of this signaling in crops could increase stress tolerance.We review methods for detecting Ca~(2+)signals,regulatory roles of Ca Ms and CMLs,binding targets,and Ca~(2+)networks under abiotic stress in organelles.

Calcium-fortified fresh milk ameliorates postmenopausal osteoporosis via regulation of bone metabolism and gut microbiota in ovariectomized rats

The aging of the global population has made postmenopausal osteoporosis prevention essential;however,pharmacological treatments are limited.Herein,we evaluate the effect of calcium-fortified fresh milk(FM)in ameliorating postmenopausal osteoporosis in a rat model established using bilateral ovariectomy.After 3 months of FM(containing vitamin D,and casein phosphopeptides,1000 mg Ca/100 g)or control milk(110 mg Ca/100 g milk)supplementation,bone changes were assessed using dual-energy X-ray absorptiometry,microcomputed tomography,and bone biomechanical testing.The results revealed that FM can regulate bone metabolism and gut microbiota composition,which act on bone metabolism through pathways associated with steroid hormone biosynthesis,relaxin signaling,serotonergic synapse,and unsaturated fatty acid biosynthesis.Furthermore,FM administration significantly increased bone mineral content and density in the lumbar spine and femur,as well as femoral compressive strength,while improving femoral trabecular bone parameters and microarchitecture.Mechanistically,we found that the effects may be due to increased levels of estrogen,bone formation marker osteocalcin,and procollagen typeⅠN-propeptide,and decreased expression of the bone resorption marker C-telopiptide and tartrate-resistant acid phosphatase 5b.Overall,the findings suggest that FM is a potential alternative therapeutic option for ameliorating postmenopausal osteoporosis.

Rapid and stable calcium-looping solar thermochemical energy storage via co-doping binary sulfate and Al–Mn–Fe oxides

Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.

Ca/Si对复合胶凝材料力学性能的影响及复合凝胶材料的水化机理

C-S-H等胶凝产物是胶凝材料力学性能的主要来源,胶凝产物主要由钙、硅和铝元素组成,钙、硅元素的比例直接影响胶凝产物的组成和结构。以脱硫石膏、粉煤灰和高炉矿粉为主要原料,制备三元复合胶凝材料,探究不同Ca/Si(0.9~1.3)对脱硫石膏-粉煤灰-高炉矿粉三元胶凝材料力学性能的影响,而后采用XRD、SEM、EDS、FTIR、TG等微观结构表征,测试分析了不同Ca/Si胶凝材料的水化机理。结果表明,最佳Ca/Si=1.1的条件下,采用SiO_(2)/Na_(2)O=1、水玻璃用量10%、水胶比0.5时,固化28 d后抗压强度达到62.2 MPa,且胶凝材料中As、Pb、Cd、Cr、Ni、Zn的浸出浓度均符合国家Ⅳ类地表水环境质量标准;合适的Ca/Si可充分促进内部钙、硅、铝元素的水化反应,可在一定程度上提高凝结时间,提高流动度,给予足够时间以促进硅酸盐、铝硅酸盐与钙的充分反应,生成足够足量的胶凝产物,提高材料致密度。

基于CRISPR/Cas系统的免扩增核酸检测技术研究进展

成簇规则间隔短回文重复序列(CRISPR)是来源于古细菌的一种免疫系统,可在特定向导RNA的引领下对外来核酸进行识别与切割。由于具有高特异性靶标识别能力以及靶激活的核酸酶活性,近年来该系统被广泛应用于核酸检测领域。为实现高灵敏检测,成簇规则间隔短回文重复序列及相关基因编码的系统(CRISPR/Cas)通常需与预扩增技术相结合,但这同时带来了扩增子气溶胶污染、依赖专有设备、检测时间延长等问题。因此,许多研究人员致力于开发免扩增CRISPR核酸检测技术以解决上述限制。CRISPR/Cas靶向激活的高周转率非特异性切割活性为这种技术的开发提供了可能性,利用各种提高系统反式切割效率或者增强信号的策略,许多免扩增CRISPR核酸检测技术被成功开发出来。该文综述了近年开发的基于CRISPR的免扩增核酸检测技术,依据策略不同将这些技术分为Cas效应器的联用或构筑生化回路、电化学传感、微体积CRISPR/Cas系统、优化信号报告物等4个方面,并从策略的角度分析了这些技术实现免扩增核酸检测的原理,即通过累积多个蛋白复合物传导的信号、增强信号传感能力、提高反应体系浓度、放大报告底物信号等原理实现灵敏度提升。基于已有的技术原理,该文对几种策略的优缺点进行讨论。此外,该文进一步展望免扩增CRISPR核酸检测技术的发展趋势并提出未来可能的研究方向,为开发更快速、灵敏、简便的分子检测技术以促进其更深入的应用提供参考。

Mg-9Al-xCa合金高温氧化行为研究

目的研究高温下Ca含量对镁合金等温氧化行为的影响,分析Ca元素在氧化过程中的作用机理,为镁合金在高温下的应用提供参考。方法以Mg-9Al-xCa合金体系为对象﹐对铸态合金组织进行分析。同时利用自主设计的实验设备在480℃下对不同Ca含量镁合金进行了不同时长的等温氧化实验,对氧化增重进行了测量,对合金氧化层进行了表征分析,并利用热力学计算揭示了作用机理。结果Mg-9Al合金中主要相组成为基体α-Mg相以及晶界处的Mg17Al12相。当添加Ca元素后,合金主要由α-Mg、晶界处的Mg17Al12相和Al_(2)Ca相组成,其中Al_(2)Ca相与α-Mg形成(α+Al_(2)Ca)共晶。随着Ca含量的增加,合金熔体凝固时生成的Mg17Al12相逐渐减少,组织中(α+Al_(2)Ca)共晶比例不断提高。在氧化200 min后,Mg-9Al合金氧化增重达到32.781 mg/cm^(2),氧化层形貌形成凸起和凹陷结构,含Ca镁合金氧化增重大幅度降低,Mg-9Al-5.0Ca氧化增重仅为0.046 mg/cm^(2),不同Ca含量镁合金氧化层形貌表现出差异性。由热力学计算得知,在Ca含量大于0.4%(质量分数)情况下,Ca元素可更容易发生氧化反应生成以CaO为主的氧化层。结论Ca含量是影响镁合金氧化行为的关键因素,随着Ca含量的增加,镁合金的抗氧化性能逐步提升。

Effect of Fluoride on the Ion-association of Calcium Phosphate and Crystallization of Hydroxyapatite

Using a titration setup to accurately control the reaction conditions and in situ monitor the reaction,we showed that fluoride exhibited negligible effects on the ion association process of calcium and phosphate and the formation of ACP nanospheres in a buffer solution with constant ionic strength.However,the stability of ACP increased with increasing fluoride concentration,which was ascribed to the inhibitory effect of fluoride on the aggregation of ACP nanospheres and the nucleation of nanocrystals on the surface of ACP nanospheres.Furthermore,fluoride could inhibit the lateral growth of HAP nanosheets and promote the formation of rod-like crystals.These results further improve our understanding of the crystallization pathway of HAP crystals and the regulatory effects of fluoride.

Purification of Produced Water from a Sour Oilfield in South Kuwait. 2. Oil-Water Separation and Crystallization of Calcium Carbonate

Oil-water separation for produced water (PW) originating from an oil extraction site in South Kuwait was carried out using bleached, esterified cellulosic material from used coffee grounds. Thereafter, earth-alkaline metal ions, specifically calcium ions, of the de-oiled PW were removed by precipitation with sodium carbonate to give access to pure sodium chloride as industrial salt from the remaining PW. While the purity of the precipitated calcium carbonate (CaCO3) depends on the precipitation conditions, CaCO3 of up to 95.48% purity can be obtained, which makes it a salable product. The precipitation of CaCO3 decreases the amount of calcium ions in PW from 11,300 ppm to 84 ppm.

Preparation of high-purity fluorite and nanoscale calcium carbonate from low-grade fluorite

Flotation separation of calcite from fluorite is a challenge on low-grade fluorite flotation that limits the recovery and purity of fluorite concentrate.A new acid leaching–flotation process for fluorite is proposed in this work.This innovative process raised the fluor-ite’s grade to 97.26wt%while producing nanoscale calcium carbonate from its leachate,which contained plenty of calcium ions.On the production of nanoscale calcium carbonate,the impacts of concentration,temperature,and titration rate were examined.By modifying the process conditions and utilizing crystal conditioning agents,calcite-type and amorphous calcium carbonates with corresponding particle sizes of 1.823 and 1.511μm were produced.The influence of the impurity ions Mn^(2+),Mg^(2+),and Fe^(3+)was demonstrated to reduce the particle size of nanoscale calcium carbonate and make crystal shape easier to manage in the fluorite leach solution system compared with the calcium chloride solution.The combination of the acid leaching–flotation process and the nanoscale calcium carbonate preparation method improved the grade of fluorite while recovering calcite resources,thus presenting a novel idea for the effective and clean usage of low-quality fluorite resources with embedded microfine particles.

High-pressure study on calcium azide(Ca(N_(3))_(2)):Bending of azide ions stabilizes the structure

The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,respectively.The compressibility of Ca(N_(3))_(2)changed as the pressure increased,and no phase transition occurred within the pressure from ambient pressure up to 54 GPa.The measured zero-pressure bulk modulus of Ca(N_(3))_(2)is higher than that of other alkali metal azides,due to differences in the ionic character of their metal-azide bonds.Using CASTEP,all vibration modes of Ca(N_(3))_(2)were accurately identified in the vibrational spectrum at ambient pressure.In the high-pressure vibration study,several external modes(ext.)and internal bending modes(ν_(2))of azide anions(N_(3)^(-))softened up to~7 GPa and then hardened beyond that pressure.This evidence is consistent with the variation observed in the F_(E)–f_(E)data analyzed from the XRD result,where the slope of the curve changes at 7.1 GPa.The main behaviors under pressure are the alternating compression,rotation,and bending of N_(3)^(-)ions.The bending behavior makes the structure of Ca(N_(3))_(2)more stable under pressure.

Changes in calcium accumulation and utilization efficiency and their impact on recycling,immobilization,and export across the oil palm cycle

Effective calcium(Ca)management is crucial for optimizing oil palm cultivation and enhancing crop yield.This study aimed to gain insights into the dynamics of Ca concentration,accumulation,exportation,immobilization,and recycling in various oil palm organs relative to plant age.The experiment was conducted at the Agropalma enterprise site in the northeastern region of Para State,Brazil,evaluating seven plant age treatments:2,3,4,5,6,7,and 8 years old.Employing a completely randomized design with four replications.The results demonstrated an age-related increase in Ca concentration in petioles,rachis,arrows,male inflorescences,peduncles,and fruits.Furthermore,Ca accumulation exhibited an upward trend in all organs with progressing plant age.Notably,the study revealed an enhanced Ca use efficiency across all plant organs in correlation with the age of oil palm cultivation.These findings underscore the dynamic nutritional demands of oil palm,influencing Ca immobilization,cycling,and export throughout its developmental stages.

Hydration Behavior and Cementitious Properties of Calcium Carbonate-aluminate Minerals Composite

The purpose of this research is to investigate the hydration behavior and cementitious properties of the mixture of calcium carbonate and aluminate, and to explore whether it can be adopted as a new low-carbon cementitious material. The composite system of calcium carbonate and aluminate minerals is studied by measuring the component of hydration products, the hydration heat, setting time and compressive strength.The results prove that the composite system has certain cementitious properties and is feasible to prepare new low-carbon cement.