Calcium Research Articles

Mechanisms of calcium-mediated As(V) immobilization by undissolved and dissolved biochar in saline-alkali environments

The environmental impact of arsenic (As) pollution has been a focal point within environmental science. In arsenic-polluted saline-alkali environment, the addition of exogenous biochar can affect the morphological transformation of As both through direct and indirect mechanisms, with calcium ions (Ca(II)) playing a crucial role. This study investigates the immobilization mechanisms of undissolved biochar (UOB) and dissolved biochar (DOB) on As(V) in the absence and presence of Ca(II) under alkaline conditions and aerobic atmosphere. While UOB and DOB alone are insufficient for As(V) immobilization, their combined action in the presence of Ca(II) achieves remarkable immobilization rates of 91.9% and 98.1%, respectively. Precipitation of calcium arsenate is identified as the primary immobilization pathway in both the UOB-Ca(II)-As(V) and DOB-Ca(II)-As(V) systems. Furthermore, Ca(II) acts as a mediator for As(V) immobilization through the formation of ternary UOB/DOB-Ca-As complexes, which are corroborated by Density Functional Theory (DFT) analysis from a microscopic perspective. Notably, the synergistic immobilization of As by DOB and newly generated CaCO3 in DOB-Ca(II)-As(V) system is highlighted. Additionally, the increase in Ca(II) concentration (0–100 mM) and solution pH (9.0–12.0) both significantly enhance the immobilization of As(V). An increase in the dosage of UOB (0.4–4 g/L) reduces the immobilization of As(V), while effect of the DOB concentration is insignificant. This study provides new insights into how the release of two biochar fractions into a typical Ca(II)-rich saline-alkali environment may alter the fate and transport of As species.

Investigation of local stimulation effects of embedding PGLA at Zusanli (ST36) acupoint in rats based on TRPV2 and TRPV4 ion channels.

Acupoint Catgut Embedding (ACE) is an extended and developed form of traditional acupuncture that serves as a composite stimulation therapy for various diseases. However, its local stimulation effects on acupoints remain unclear. Acupuncture can activate mechanically sensitive calcium ion channels, TRPV2 and TRPV4, located on various cell membranes, promoting Ca2+ influx in acupoint tissues to exert effects. Whether ACE can form mechanical physical stimulation to regulate these channels and the related linkage effect requires validation. This study investigates the influence of TRPV2 and TRPV4 ion channels on the local stimulation effects of ACE by embedding PGLA suture at the Zusanli (ST36) acupoint in rats and using TRPV2 and TRPV4 inhibitors. Flow cytometry, immunofluorescence, Western blot, and Real-time quantitative PCR were employed to detect intracellular Ca2+ fluorescence intensity, the expression of macrophage (Mac) CD68 and mast cell (MC) tryptase, as well as the protein and mRNA expression of TRPV2 and TRPV4 in acupoint tissues after PGLA embedding. The results indicate that ACE using PGLA suture significantly increases the mRNA and protein expression of TRPV2 and TRPV4, Ca2+ fluorescence intensity, and the expression of Mac CD68 and MC tryptase in acupoint tissues, with these effects diminishing over time. The increasing trends are reduced after using inhibitors, particularly when both inhibitors are used simultaneously. Furthermore, correlation analysis shows that embedding PGLA suture at the ST36 acupoint regulates Mac and MC functions through Ca2+ signaling involving not only TRPV2 and TRPV4 but multiple pathways. These results suggest that embedding PGLA suture at the ST36 acupoint generates mechanical physical stimulation and regulates TRPV2 and TRPV4 ion channels, which couple with Ca2+ signaling to form a linkage effect that gradually weakens over time. This provides new reference data for further studies on the stimulation effects and clinical promotion of ACE.

Effective removal of Calcium and Magnesium Ions from boiler feed Water using Polyacrylonitrile supported titanium tungstovanadate composite ion exchange nanofiber

<p><em><strong>​​​​​​</strong></em><span style="font-family:"Times New Roman","serif";font-size:12.0pt;line-height:150%;">The challenge posed by the presence of calcium ions (Ca<sup>2+</sup>) in process streams is attributed to its adverse effects on the heat transfer efficiency of process equipment. In this study, a novel electrospun nanofibrous composite was synthesized by combining polyacrylonitrile (PAN) with well-dispersed Titanium tungestovanadate (TWV) cation exchanger. Homogeneous precipitation technique was employed to synthesize nano-titanium (IV) tungstovanadate (TWV) cation exchanger. Various synthesis parameters, including reactant volume ratio, amount of precipitating agent and reaction temperature, were optimized to achieve the highest ion exchange capacity (IEC). The prepared ion exchange material exhibited an ion exchange capacity (IEC) of 2.39 meq.g<sup>-1</sup> for Na<sup>+</sup> ions. The incorporation of the prepared nanoparticles into nanofibers conferred the sorption capabilities of the composite. The nanofibers' morphologies and structures were analyzed using Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Batch sorption experiments were carried out to investigate the sorption properties. Controlled experiments were conducted to investigate the impact of various factors, including solution pH, temperature, dosage, contact time, and the initial concentration of the hard water. The results indicated that the optimum adsorption conditions that gave the highest percentage of removal 99%, 98% for Ca<sup>2+</sup> and Mg<sup>2+</sup>  ions respectively were 50 mg of adsorbent dosage, 500 ppm of Ca<sup>2+</sup> and Mg<sup>2+</sup>  solution =7, and a contact time of 30 min at room temperature .The  kinetic data were fitted to pseudo second order model. Furthermore, the thermodynamic study suggested that the adsorption on PAN/TWV NF was endothermic and spontaneous.</span></p>

Effects of exogenous calcium and calcium inhibitor on physiological characteristics of winter turnip rape (Brassica rapa) under low temperature stress

Low temperature is one of the environmental factors that restrict the growth and geographical distribution of Brassica. To investigate the effects of exogenous calcium and calcium inhibitor on the ability of winter turnip rapeseed (Brassica rapa L.) to withstand low temperatures (4℃), we used a strong cold-resistant variety Longyou 7 (L7) and a weak cold-resistant variety Longyou 99 (L99) as the materials. The seedlings were treated with CaCl2 (20 mmol·L-1) and calcium inhibitor LaCl3 (10 mmol·L-1) at 0 h (CK), 6 h, 12 h, 24 h and 48 h after 4℃ treatments. Physiological characteristics, Ca2+ flux and Ca2+ concentration in roots after treatments were analyzed. Results illustrated that under 4℃ treatment, activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased by both CK and exogenous CaCl2 treatments. Contents of soluble protein (SP) and proline (Pro) increased, while contents of malondialdehyde (MDA) decreased, resulting in reduced membrane lipid peroxidation. But enzyme activity decreased and MDA content increased following treatment with exogenous LaCl3. The rate of Ca2+ flow showed a higher uptake in L7 roots compared with L99. L99 showed Ca2+ efflux with a rate of 30.21 pmol‧cm-2‧s-1, whereas L7 showed short efflux then returned to influx. Calcium ion content in roots decreased in both cultivars after CaCl2 treatment. Results of RNA-seq revealed that genes were differentially expressed in response to low temperatures, hormones, photosystem II, chloroplasts, DNA replication, ribosomal RNA processing, and translation. This study found significant expression genes related to cellular signal transduction (MAPK signaling pathway) and material metabolism (nitrogen metabolism, glycerol ester metabolism).It was also analyzed by WGCNA that two modules had the strongest correlation with physiological indicators. Eight candidate genes were identified among MAPK signaling pathway and the two modules.

Altered Expression of Thyroid- and Calcium Ion Channels-Related Genes in Rat Testes by Short-Term Exposure to Commercial Herbicides Paraquat or 2,4-D.

Exposure to pesticides such as paraquat and 2,4-dichlorophenoxyacetic acid (2,4-D) has been linked to harmful health effects, including alterations in male reproduction. Both herbicides are widely used in developing countries and have been associated with reproductive alterations, such as disruption of spermatogenesis and steroidogenesis. The thyroid axis and Ca2+-permeable ion channels play a key role in these processes, and their disruption can lead to reproductive issues and even infertility. This study evaluated the short-term effects of exposure to commercial herbicides based on paraquat and 2,4-D on gene expression in rat testes. At the molecular level, exposure to paraquat increased the expression of the thyroid hormone transporters monocarboxylate transporter 8 (Mct8) and organic anion-transporting polypeptide 1C1 (Oatp1c1) and the thyroid receptor alpha (TRα), suggesting a possible endocrine disruption. However, it did not alter the expression of the sperm-associated cation channels (CatSper1-2) or vanilloid receptor-related osmotically activated channel (Trpv4) related to sperm motility. In contrast, exposure to 2,4-D reduced the expression of the Mct10 transporter, Dio2 deiodinase, and CatSper1, which could affect both the availability of T3 in testicular cells and sperm quality, consistent with previous studies. However, 2,4-D did not affect the expression of CatSper2 or Trpv4. Deregulation of gene expression could explain the alterations in male reproductive processes reported by exposure to paraquat and 2,4-D. These thyroid hormone-related genes can serve as molecular biomarkers to assess endocrine disruption due to exposure to these herbicides, aiding in evaluating the health risks of pesticides.

Regulation of vascular smooth muscle cell contraction during early postnatal ontogenesis

Growth of the body in early postnatal ontogenesis is associated with changes in the functioning of many organ systems, including the cardiovascular system. The circulatory system of newborns is characterized by numerous structural and functional features, which at the systemic level is manifested in a significantly lower level of blood pressure. This review describes the differences in the mechanisms of regulation of vascular smooth muscle cell contraction in early postnatal ontogenesis and in adulthood, including age-related changes in the functioning of ion channels, which activity affects membrane potential level and intracellular concentration of calcium ions, as well as changes in calcium sensitivity of the contractile apparatus. The final section of the review discusses the connection between the mechanisms regulating contraction and differentiation of vascular smooth muscle cells during maturation.

The role of NAADP in maintaining spontaneous heart contractions: comparative physiological studies

The goal of the work was to study the role of the second messenger NAADP (Nicotinic Acid Adenine Dinucleotide Phosphate), which causes the release of Ca2+ ions from lysosomes and endosomes, in the regulation of heart contractions. Isolated hearts of the grape snail Helix pomatia and a chicken embryo were used as models. Using the membrane-permeable acetooxymethyl ester NAADP-AM, we showed that NAADP at nanomolar concentrations increases the frequency and amplitude of spontaneous cardiac contractions in H. pomatia. The NAADP antagonist NED19, without affecting the amplitude of contractions, dose-dependently reduces their frequency, completely blocking spontaneous contractions of the mollusk heart at a concentration of 5 μM. The V-type H+-ATPase inhibitor bafilomycin A1 suppresses the accumulation of calcium ions in lysosomes and acidic endosomes. We have shown that bafilomycin A1 causes attenuation of spontaneous contractions and cardiac arrest in H. pomatia. Serotonin increases the amplitude of contractions of the H. pomatia heart without affecting heart rate. NED19 at saturating concentrations (10 μM) reduces the frequency of contractions when the snail heart is activated by serotonin, but only partially reduces their amplitude. In experiments with the isolated chick embryo heart, we showed that NED19 reduces the frequency of spontaneous contractions without affecting the amplitude of contractions. Based on the data obtained, a hypothesis was put forward that the release of calcium ions from lysosomes and endosomes under the influence of endogenous NAADP ensures the maintenance of spontaneous contractions of the heart.

Producción de esterasa por Fusarium culmorum crecido en presencia de diferentes concentraciones di(2-etilhexil) ftalato y de ion calcio en fermentación sumergida

Phthalates are plastic additives used as plasticizers in the manufacture of flexible plastic materials. These compounds, such as di(2-ethylhexyl) phthalate (DEHP) are toxic substances to the environment and human health, and have been detected as environmental pollutants. In this study, the activity of esterase produced by Fusarium culmorum grown in media supplemented with different concentrations of DEHP (1.5, 3 and 4 g/L) and calcium ion (0.1 and 0.5 g/L) in submerged fermentation was characterized by biochemical tests and polyacrylamide gel electrophoresis. The greatest esterase activity was observed in cultures grown in media added with 3 g of DEHP/L and 0.5 g of calcium ion/L, followed by those cultures grown in media containing 1.5 g of DEHP/L. Whereas cultures grown on 4 g of DEHP/L had the lowest esterase activity. In general, cultures added with 0.5 g of calcium ion/L had the maximum enzymatic activity and the highest enzymatic productivity in the media tested. High concentration of DEHP were used as the sole source of carbon and energy by F. culmorum. It is suggested that the calcium ion favored the esterase production during the DEHP biodegradation. However, further studies are needed to understand the relationship between calcium ion, fungal growth, and enzyme production to provide the appropriate concentration of this ion in the culture medium.

Effect of mineralized solution on protective properties of clays in radioactive waste isolation

In this paper there were studied the mineral composition and sorption properties as well as filtration properties of natural clay samples from “Gorodnoe” deposit of Brest region and “Markovskoe” deposit of Gomel region. It was determined that clay mineral montmorillonite of the samples contains illite phase in the structure, which is 4,8 wt.% in “Gorodnoe” sample and 3,6 wt.% in “Markovskoe” sample. The illite phase was shown to contain highly selective sorption sites for 137Cs. 85Sr sorption mostly takes place on montmorillonite. It was determined that model mineralized solution (the solution imitating chemical composition of water solution if water penetrates a radioactive waste disposal and consequently passes through concrete, Na-bentonite and again concrete layers) doesn’t affect 137Cs sorption, but significantly affects 85Sr sorption. Distribution coefficients (Kd ) of 137Cs sorption on studied clay samples are higher than 103 dm3 /kg, indicating high sorption properties of the clays towards 137Cs. Kd 85Sr for sorption on the clay samples in the model mineralized solution is 30 times lower than Kd 137Cs mostly because of competition between strontium and calcium ions. It was determined that filtration coefficient values of clays from “Gorodnoe” and “Markovskoe” deposits are 2,4 and 1,3 times higher after being treated with the model mineralized solution than the filtration coefficient values for raw clay samples. Hence, the clay from “Markovskoe” deposit is more resistant to the influence of the model mineralized solution than the clay from “Gorodnoe” deposit. The overall results of the research state that the clay from “Markovskoe” deposit can be used in the underlying layer of low- and medium-level radioactive waste disposal facility at NPP.

Computational Fuzzy Modelling Approach to Analyze Neuronal Calcium Dynamics With Intracellular Fluxes.

Mathematical neuroscience investigates how calcium distribution in nerve cells affects the neurological system. The interaction of numerous systems is necessary for the operation of several cellular processes in neuron cells, such as calcium, buffer, ER etc. The dynamics of interacting parameters give useful information on neural cell function. This work uses a mathematical model to analyze the dynamic interactions of buffer and ER inside neurons, considering their spatial properties. While buffers bind to calcium ions and lower their concentration, the endoplasmic reticulum (ER) serves as a reservoir, holding a significant number of free calcium ions. The uncertainty of initial values of calcium concentration poses challenges for researchers to develop calcium signaling models. In this article, we examined the exact solution and approximate solution of the mathematical model that was analyzed using the fuzzy undetermined coefficient approach. MATLAB is being used to perform the simulation. Endoplasmic reticulum and buffer have been found to have a substantial impact on calcium signaling. Fuzzy differential equation Provides a useful tool for evaluating complicated processes with imprecise values when ordinary differential equations perform not precisely. They allow for the examination of dynamic processes under fuzzy settings, which contributes to advances research.

Hierarchical Integration of Curcumin-Loaded CaCO3 Nanoparticles and Black Phosphorus Nanosheets in Core/Shell Nanofiber for Cranial Defect Repair.

Reconstruction and healing of large craniofacial bone defects are major clinical challenges due to high risk of chronic inflammation and reduced cell mineralization levels. Herein, a core-shell nanofiber-based implant with significant pro-osteogenesis capability for treating skull defects is reported, which is hierarchically integrated with curcumin-loaded calcium carbonate nanoparticles (CaCO3@Cur NPs) in the outer layers and black phosphorus nanosheets (BPNSs) in the core compartments. The radical alignment of the integrated nanocomponents allows the sequential in situ release of the therapeutic agents in a controlled manner after implantation. Curcumin can repolarize M1 macrophages into M2 phenotypes for anti-inflammation purposes. Meanwhile, the released calcium and phosphate ions can promote the biomineralization of hydroxyapatite at the defect site and facilitate bone regeneration. Evaluations on cranial defect-bearing rat models demonstrated that the electrospun fibers in the present study substantially promoted restoration of the damaged skulls and inhibited inflammation in the wound bed. This strategy provides a new idea for the treatment of skull defects in the clinic.

Optimizing light intensity and airflow for improved lettuce growth and reduced tip burn disease in a plant factory

In practical plant factory production, light intensity and airflow were major environmental factors that significantly impacted lettuce growth and tip burn disease. This study investigated the effects of light intensity (100, 200, and 300 μmol·m-2·s-1) and airflow rate (100, 200, and 300 m³/h) on the comprehensive quality of lettuce. The Analytic Hierarchy Process (AHP) was employed to determine the weight of various growth and physiological indices of lettuce, while fuzzy mathematics principles were used to evaluate its comprehensive indices. The findings revealed that higher light intensity increased Ca2+ demand and decreased stomatal conductance, exacerbating tip burn disease. In contrast, increasing the airflow rate reduced leaf temperature, promoted transpiration, and facilitated calcium ion transport, thereby alleviating the occurrence of tip burn. Increasing the airflow rate to 300 m³/h effectively improved plant transpiration and Ca²⁺ transport, which further reduced tip burn. The comprehensive results indicated that under the conditions of a light intensity of 200 μmol·m-2·s-1 and an airflow rate of 300 m³/h, lettuce achieved the best comprehensive quality score of 0.6490, with a Ca2+ content of 21.83 mg/100 g, and tip burn was effectively suppressed. The study provided valuable scientific support for the precise control of environmental conditions in plant factories.

Berberine and palmatine, acting as allosteric potential ligands of α7 nAChR, synergistically regulate inflammation and phagocytosis of microglial cells.

Berberine and palmatine are isoquinoline quaternary alkaloids derived from Chinese medicinal herbs. These alkaloids have shown promising synergy in inhibiting acetylcholinesterase (AChE), indicating their potential in treating Alzheimer's disease (AD). Besides, the anti-inflammatory effects of berberine and palmatine have been widely reported, although the underlying mechanism remains unclear. Here, we found that berberine and palmatine could induce calcium ion (Ca2+) influx via activating α7 nicotinic acetylcholine receptor (α7 nAChR) in cultured microglial cells, possibly serving as its allosteric potential ligands. Furthermore, we examined the synergistic anti-inflammatory effects of berberine and palmatine in the LPS-induced microglia, that significantly suppressed the production of TNF-α and iNOS. Notably, this suppression was reversed by co-treatment with a selective antagonist of α7 nAChR. Moreover, the alkaloid-induced microglial phagocytosis was shown to be mediated by the induction of Ca2+ influx through α7 nAChR and subsequent CaMKII-Rac1-dependent pathway. Additionally, the combination of berberine and palmatine, at low concentration, protected against the LPS-induced endoplasmic reticulum stress and mitochondrial dysfunction in microglia. These findings indicate the potential of berberine and palmatine, either individually or in combination, in contributing to anti-AD drug development, which provide valuable insights into the mechanisms by which natural products, such as plant alkaloids, exert their anti-AD effects.

Analysis of Differential Gene Expression under Acute Lead or Mercury Exposure in Larval Zebrafish Using RNA-Seq.

This study was first conducted to investigate the effects of acute lead exposure on developing zebrafish embryos or larvae from 24 to 120 h post-fertilization (hpf). Our data showed that treatment with 50-200 μM lead significantly affected larval survivability and morphology compared to the respective control. Second, we chose 120 hpf larvae treated with 12.5 μM lead for RNA sequencing due to its exposure level being sufficient to produce toxic effects with minimum death and lead bioaccumulation in developing zebrafish. A total of 137.45 million raw reads were obtained, and more than 86% of clean data were mapped to the zebrafish reference genome. Differential expression profiles generated 116 up- and 34 down-regulated genes upon lead exposure. The most enriched GO terms for representative DEGs were ion transport and lipid metabolism. Third, a comparison with the dataset of mercury-regulated gene expression identified 94 genes (64 up-regulated and 30 down-regulated) for exposure specific to lead, as well as 422 genes (338 up-regulated and 84 down-regulated) for exposure specific to mercury. In addition, 56 genes were co-regulated by micromolar mercury and lead treatment, and the expression of thirteen genes, including mt2, ctssb.1, prdx1, txn, sqrdl, tmprss13a, socs3a, trpv6, abcb6a, gsr, hbz, fads2, and zgc:92590 were validated by qRT-PCR. These genes were mainly associated with metal ion binding, proteolysis, antioxidant activity, signal transduction, calcium ion or oxygen transport, the fatty acid biosynthetic process, and protein metabolism. Taken together, these findings help better understand the genome-wide responses of developing zebrafish to lead or mercury and provide potential biomarkers for acute exposure to toxic metals.

Unveiling the dissolution mechanism of calcium ions from CSH substrates in Na2SO4 solution: Effects of Ca/Si ratio

The decalcification behavior of calcium silicate hydrate (CSH) under sulfate attack poses a critical challenge to the long-term durability of cement-based infrastructure, yet understanding its underlying microscopic mechanisms remains elusive. This study employs molecular dynamics to compare the differences in calcium ion dissolution capability of CSH substrates with varying Ca/Si ratios under sulfate solution exposure. The results show that the dissolution amount and dissolution efficiency of Ca are positively correlated with Ca/Si, and the root cause depends on the basic structure of CSH. With the increase of Ca/Si, the electronegativity of CSH decreases, and the adsorption capacity and stability of cations weaken. Meanwhile, Ca ions are less limited by the silicate chain coordination, water molecules are more likely to invade the substrate interior and replace the Ca ions. This research aims to provide a molecular basis for cement production and durability applications in marine engineering.

Three‐Pronged Induction of Tumor Calcification Synergistic Calcium Immunotherapy Enables Diagnosis and Cure of Cancer

AbstractTumor calcification is considered to have the superiority of integrating tumor diagnosis and treatment, and it also has been found to be a predictor of favorable prognosis. However, selecting suitable nanocarriers and therapeutic drugs to maximize the tumor calcification efficiency are key factors for improving calcification‐medicated theranostics. This study performs a multi‐channel calcification nanoinitiator (CalNI, i.e., BP‐Cur‐Ca@PKLAK) by loading curcumin (Cur) and depositing Ca2+ on black phosphorus (BP) and combined carrying mitochondria‐targeting cytotoxic peptide KLAK to boost a triple‐induced tumor calcification. CalNI preferentially accumulates inside tumor mitochondria and induces multilevel calcification promotion by the three combined effects of (i) the degradation of BP into PO43− provides the phosphorus source required for calcification; (ii) burst of calcium ions can directly induce cellular calcium overload; (iii) Cur can inhibit calcium efflux thus further aggravate intracellular calcium stress. Moreover, KLAK exhibited enhanced mitochondrial synergistic toxic effects. Notably, the potential function of CalNI on the regulation of macrophage polarization could completely reverse the immunosuppressive microenvironment, and activate the initiation of T cell‐mediated immune response. Therefore, this three‐pronged CalNI showed a huge promise to be an alternative to conventional oncology therapy, which presents a more satisfactory therapeutic efficiency than any kind of single induction mode.

Effect of Magnetic Field and Magnetic Nanoparticles on Choice of Endothelial Cell Phenotype

Background. Endothelial cells as participants in angiogenesis choose their phenotype as tip cells (leading, migratory) or stalk cells (following). It has been experimentally found and theoretically modeled that rapid oscillations in intracellular calcium concentration play a key role in controlling phenotype selection and possible vessel architecture. In addition, the intracellular calcium concentration in endothelial cells is known to be regulated by mechanical wall shear stress induced by blood flow, which controls mechanosensitive calcium ion channel gating. Experimental methods of controlling mechanosensitive ion channel gating in external magnetic fields with application of magnetic nanoparticles are developed that affect magnetic nanoparticles artificially attached to cell membranes. Objective. A key question is raised about the possibility of controlled selection of endothelial cell phenotype in external magnetic fields due to the presence of artificial or biogenic magnetic nanoparticles embedded in the cell membrane. Methods. The magnetic wall shear stress is calculated due to the influence of the external magnetic field on the magnetic nanoparticles embedded in the cell membrane, which controls the mechanosensitive calcium ion pathways. Numerical modeling of oscillations in intracellular calcium concentration in endothelial cells and determination of their final phenotype was carried out taking into account intercellular communication. The python programming language and scipy, py-pde, matplotlib packages of the python programming language were used for numerical modeling. Results. The magnetic field flux density and frequency ranges of a uniform rotating magnetic field, as well as the magnitude of the gradient and the frequency of a non-uniform oscillating magnetic field were calculated for controlling the amplitude and frequency of intracellular calcium concentration oscillations in endothelial cells, as well as the selection of their phenotype. It opens the perspective of controlling angiogenesis and vessel architecture. Conclusions. Phenotype selection by endothelial cells can be controlled in a uniform rotating external magnetic field, as well as in a non-homogeneous oscillating magnetic field.

Coarse-Graining the Recognition of a Glycolipid by the C-Type Lectin Mincle Receptor.

Macrophage inducible Ca2+-dependent lectin (Mincle) receptor recognizes Mycobacterium tuberculosis glycolipids to trigger an immune response. This host membrane receptor is thus a key player in the modulation of the immune response to infection by M. tuberculosis and has emerged as a promising target for the development of new vaccines against tuberculosis. The recent development of the Martini 3 force field for coarse-grained (CG) molecular modeling allows the study of interactions of soluble proteins with small ligands which was not typically modeled well with the previous Martini 2 model. Here, we present a refined approach detailing a protocol for modeling interactions between a glycolipid and its receptor at a CG level using the Martini 3 force field. Using this approach, we studied Mincle and identified critical parameters governing ligand recognition, such as loop flexibility and the regulation of hydrophobic groove formation by calcium ions. In addition, we assessed ligand affinity using free energy perturbation calculations. Our results offer mechanistic insight into the interactions between Mincle and glycolipids, providing a basis for the rational design of molecules targeting this type of membrane receptors.

Carbonized seawater cement slurries for offshore deep cement mixing: Carbonation mechanism, strength enhancement and microstructure evolution

Seawater cement slurry (SCS) is a commonly used binder in offshore deep cement mixing (DCM) construction. Seawater cement slurries are usually prepared before they are grouted into the seabed and mixed with marine clay. The aim of this study is to explore the feasibility of applying carbonation technology to fabricate SCS suitable for offshore DCM while achieving carbon sequestration and obtaining better mechanical properties for stabilised marine sediments.This study demonstrated that after appropriate carbonation, carbonized SCS can be used in DCM to replace conventional SCS. Short-term carbonation promotes cement dissolution and hydration rates under seawater conditions rich in magnesium, calcium, and other inorganic ions. The carbonates include calcite, vaterite and amorphous carbonates, which provide additional nucleation sites for the hydration of SCS, resulting in an increment for amorphous CS(A)H gel with a dense pore structure and binding interaction with soil particles. After carbonation with 20 % CO2 for 5 min (0.5 wt% of cement), the UCS and secant modulus of cement-soil mixtures by 15.7 % and 111 % at the age of 1 day, and by 6.82 % and 10 % at the age of 28 days when treating marine clay with 80 % moisture content at a dosage of 260 kg/m3.

Influence of Steel and Poly Vinyl Alcohol Fibers on the Development of High-Strength Geopolymer Concrete

The present study focuses on the mechanical performance of steel and polyvinyl alcohol fibers embedded in the geopolymer matrix. A high-strength geopolymer concrete with fly ash, slag and silica fume as precursors and sodium hydroxide and sodium silicate solutions as activators has been tested for its strength in compression and flexure. The influence of fibers on flowability, long-term shrinkage and sulphuric acid attack on the geopolymer concrete has also been studied. The dosage of fibers was maintained at 1%, 2% and 3% by volume, and fibers of length 13 mm have been used in the study. Results indicate that slag with 3% steel fibers by volume had a predominant influence on the strength development of steel fiber-reinforced geopolymer concrete, yielding a compressive strength of 107 MPa after 28 days. Blast furnace slag resulted in increasing the shrinkage of concrete due to rapid gel formation owing to the presence of calcium ions, although the fibers helped reduce the shrinkage to some extent. The strength of steel fiber geopolymer concrete was superior to PVA fiber geopolymer concrete; however, after an acid attack, the strength of steel fiber geopolymer concrete was reduced more than PVA fiber geopolymer concrete due to the enhanced corrosion resistance of PVA fibers.