Amount Of Ca Research Articles

Using a Failing Human Ventricular Cardiomyocyte Model to Re-Evaluate Ca2+ Cycling, Voltage Dependence, and Spark Characteristics

Previous studies have observed alterations in excitation–contraction (EC) coupling during end-stage heart failure that include action potential and calcium (Ca2+) transient prolongation and a reduction of the Ca2+ transient amplitude. Underlying these phenomena are the downregulation of potassium (K+) currents, downregulation of the sarcoplasmic reticulum Ca2+ ATPase (SERCA), increase Ca2+ sensitivity of the ryanodine receptor, and the upregulation of the sodium–calcium (Na=-Ca2+) exchanger. However, in human heart failure (HF), debate continues about the relative contributions of the changes in calcium handling vs. the changes in the membrane currents. To understand the consequences of the above changes, they are incorporated into a computational human ventricular myocyte HF model that can explore the contributions of the spontaneous Ca2+ release from the sarcoplasmic reticulum (SR). The reduction of transient outward K+ current (Ito) is the main membrane current contributor to the decrease in RyR2 open probability and L-type calcium channel (LCC) density which emphasizes its importance to phase 1 of the action potential (AP) shape and duration (APD). During current-clamp conditions, RyR2 hyperphosphorylation exhibits the least amount of Ca2+ release from the SR into the cytosol and SR Ca2+ fractional release during a dynamic slow–rapid–slow (0.5–2.5–0.5 Hz) pacing, but it displays the most abundant and more lasting Ca2+ sparks two-fold longer than a normal cell. On the other hand, under voltage-clamp conditions, HF by decreased SERCA and upregulated INCX show the least SR Ca2+ uptake and EC coupling gain, as compared to HF by hyperphosphorylated RyR2s. Overall, this study demonstrates that the (a) combined effect of SERCA and NCX, and the (b) RyR2 dysfunction, along with the downregulation of the cardiomyocyte’s potassium currents, could substantially contribute to Ca2+ mishandling at the spark level that leads to heart failure.

1-(3-Aminopropyl) imidazole (APIm) modified ultrafiltration (UF) membrane for mitigating alginate fouling caused by calcium

UF is widely used as a wastewater treatment and recycling technology. However, membrane fouling is still an important factor affecting the wide application. In this study, APIm with positive amino group was adsorbed to the surface of the carboxylated polyacrylonitrile (PAN) membrane by electrostatic force to reduce the fouling of sodium alginate (SA) caused by Ca2+. The results show that 1 v/v% APIm was selected as the optimal dosage, accompanied by the highest water flux of 330.5 L·m-2h−1 bar−1 and bovine serum albumin (BSA) rejection rate of 91.0 %. When the concentration of Ca2+ was increased to 10 mM, the Ca2+ catch amount increased to 48.25 mg/cm2. The main anti-fouling mechanism was that APIm captured a certain amount of Ca2+ in situ, destroyed the complex structure of sodium alginate (SA) and Ca2+. Then the fouling layer was easy to be removed by physical cleaning. At the concentration of 10 mM Ca2+, the membrane flux recovery rate of 1 v/v% APIm membrane was increased to 80.1 %. This study demonstrates a fouling control strategy for in-situ removal of Ca2+ bound SA fouling, providing a new approach for the future development of UF membrane.

Fish Development in Lake Ecosystems, Effect of Heavy Metals

Heavy metals enter the water bodies and combine with the water buffer system, then turn into poorly soluble hydroxides, carbonates, sulfides and phosphates, and also form metal-organic complexes, accumulate in the bottom sediments and in general in the bodies of the fish fauna of the reservoirs of the area, seriously affecting their development. It was determined that the amount of Ca2+ ions varied from 17 mg/l to 112 mg/l, and the amount of Mg2+ ions from 5.5 mg/l to 83.5 mg/l, in other words, towards autumn. water hardness has increased. The amount of alkali metal (Na+ + K+) ions is much lower in spring than in summer and autumn. According to the cations, the amount of chloride and sulfate ions increases in autumn. Thus, the impact of anthropogenic factors on fish is diverse and manifests itself primarily in morphological anomalies and changes in the basic biological parameters of fish populations. The main of them is the reduction of productivity and the complete loss of their natural forms, the increase of individuals and the increase of mortality.

Tunable Oxidized-Chitin Hydrogels with Customizable Mechanical Properties by Metal or Hydrogen Ion Exposure.

This study focuses on the optimization of chitin oxidation in C6 to carboxylic acid and its use to obtain a hydrogel with tunable resistance. After the optimization, water-soluble crystalline β-chitin fibrils (β-chitOx) with a degree of functionalization of 10% were obtained. Diverse reaction conditions were also tested for α-chitin, which showed a lower reactivity and a slower reaction kinetic. After that, a set of hydrogels was synthesized from β-chitOx 1 wt.% at pH 9, inducing the gelation by sonication. These hydrogels were exposed to different environments, such as different amounts of Ca2+, Na+ or Mg2+ solutions, buffered environments such as pH 9, PBS, pH 5, and pH 1, and pure water. These hydrogels were characterized using rheology, XRPD, SEM, and FT-IR. The notable feature of these hydrogels is their ability to be strengthened through cation chelation, being metal cations or hydrogen ions, with a five- to tenfold increase in their storage modulus (G'). The ions were theorized to alter the hydrogen-bonding network of the polymer and intercalate in chitin's crystal structure along the a-axis. On the other hand, the hydrogel dissolved at pH 9 and pure water. These bio-based tunable hydrogels represent an intriguing material suitable for biomedical applications.

ВЛИЯНИЕ МАКРОЭЛЕМЕНТОВ, СОДЕРЖАЩИХСЯ В РАСТЕНИЯХ ПАСТБИЩ ЗАО «ПЛЕМЗАВОД КРАСНОТУРАНСКИЙ» (КРАСНОТУРАНСКИЙ РАЙОН, КРАСНОЯРСКИЙ КРАЙ), НА КАЧЕСТВО МОЛОКА КОРОВ КРАСНО-ПЕСТРОЙ ПОРОДЫ

The purpose of the study is to identify macrochemical elements in plants that affect the quality of milk in cows of the red-motley breed of CJSC Plemzavod Krasnoturansky, Krasnoturansk District of the Kras-noyarsk Region. Objectives: study and identification of macrochemical elements in plants K+, Ca2+, PO34–, Mg2+; determination of the composition of phytogroups and testing of hay for macrochemical composition; study of the content of phosphoproteins and phospholipids in cow's milk. Based on the chemical composition, macrochemical elements were identified in plants. The most significant macrochemical elements Ca2+, PO34– for the quality of cow's milk have been identified. The highest Ca2+ content is 11.32 % in Bupleurum bicaule Helm., 11 % in Medicago sativa L.; PO34– – 2.7 % in Vicia sativa L. and 1.90 % in Bupleurum bicaule. The study used the methods of test sites used in geobotanical studies of ecological and biological factors affecting the quality of cows' milk using macrochemical analysis. The qualitative composition of chemical elements in the ash residue is determined. Fluctuations were noted in the content of macrochemical elements in the ash non-combustible residue during the seasons of the year. By autumn, the amount of Ca2+ and Mg2+ increases, and PO34– decreases. Studies were conducted on the in-fluence of Ca2+, PO34– on the formation of phosphoproteins and phospholipids in cow's milk. In summer (July) milk has a high fat content, in winter (February) – protein. Statistical processing of the data was carried out by calculating the percentage of organic matter using the ratio formula. The pastures of JSC Plemzavod Krasnoturansky belong to the zone-zonal groups: forest-steppe, forest-meadow, alpine, subalpine, located in the vicinity of the villages of Krasnoturansk and Lebyazhye, in the areas of the Unyuk and Turan mountain heights. The content of macroelements in the studied pastures of the farm was determined. Identification of macrochemical elements in plants provides an understanding of the influence of plants on the quality of cows' milk (nutritional value, value).

Visible Light Motivated the Photocatalytic Degradation of P-Nitrophenol by Ca2+-Doped AgInS2.

4-Nitrophenol (4-NP) is considered a priority organic pollutant with high toxicity. Many authors have been committed to developing efficient, green, and environmentally friendly technological processes to treat wastewater containing 4-NP. Here, we investigated how the addition of Ca2+ affects the catalytic degradation of 4-NP with AgInS2 when exposed to light. We synthesized AgInS2 (AIS) and Ca2+-doped AgInS2 (Ca-AIS) with varying amounts of Ca2+ using a low-temperature liquid phase method. The SEM, XRD, XPS, HRTEM, BET, PL, and UV-Vis DRS characteristics were employed to analyze the structure, morphology, and optical properties of the materials. The effects of different amounts of Ca2+ on the photocatalytic degradation of 4-NP were investigated. Under visible light illumination for a duration of 120 min, a degradation rate of 63.2% for 4-Nitrophenol (4-NP) was achieved. The results showed that doping with an appropriate amount of Ca2+ could improve the visible light catalytic activity of AIS. This work provides an idea for finding suitable cheap alkaline earth metal doping agents to replace precious metals for the improvement of photocatalytic activities.

Lattice capacity-dependent activity for CO2 methanation: crafting Ni/CeO2 catalysts with outstanding performance at low temperatures.

In the pursuit of understanding lattice capacity threshold effects of oxide solid solutions for their supported Ni catalysts, a series of Ca2+-doped CeO2 solid solutions with 10 wt% Ni loading (named Ni/CaxCe1-xOy) was prepared using a sol-gel method and used for CO2 methanation. The lattice capacity of Ca2+ in the lattice of CeO2 was firstly determined by the XRD extrapolation method, corresponding to a Ca/(Ca + Ce) molar ratio of 11%. When the amount of Ca2+ in the CaxCe1-xOy supports was close to the CeO2 lattice capacity for Ca2+ incorporation, the obtained Ni/Ca0.1Ce0.9Oy catalyst possessed the optimal intrinsic activity for CO2 methanation. XPS, Raman spectroscopy, EPR and CO2-TPD analyses revealed the largest amount of highly active moderate-strength alkaline centers generated by oxygen vacancies. The catalytic reaction mechanisms were revealed using in situ IR analysis. The results clearly demonstrated that the structure and reactivity of the Ni/CaxCe1-xOy catalyst exhibited the lattice capacity threshold effect. The findings offer a new venue for developing highly efficient oxide-supported Ni catalysts for low-temperature CO2 methanation reaction and enabling efficient catalyst screening.

Super-Resolution Analysis of the Origins of the Elementary Events of ER Calcium Release in Dorsal Root Ganglion Neurons.

Coordinated events of calcium (Ca2+) released from the endoplasmic reticulum (ER) are key second messengers in excitable cells. In pain-sensing dorsal root ganglion (DRG) neurons, these events can be observed as Ca2+ sparks, produced by a combination of ryanodine receptors (RyR) and inositol 1,4,5-triphosphate receptors (IP3R1). These microscopic signals offer the neuronal cells with a possible means of modulating the subplasmalemmal Ca2+ handling, initiating vesicular exocytosis. With super-resolution dSTORM and expansion microscopies, we visualised the nanoscale distributions of both RyR and IP3R1 that featured loosely organised clusters in the subplasmalemmal regions of cultured rat DRG somata. We adapted a novel correlative microscopy protocol to examine the nanoscale patterns of RyR and IP3R1 in the locality of each Ca2+ spark. We found that most subplasmalemmal sparks correlated with relatively small groups of RyR whilst larger sparks were often associated with larger groups of IP3R1. These data also showed spontaneous Ca2+ sparks in <30% of the subplasmalemmal cell area but consisted of both these channel species at a 3.8-5 times higher density than in nonactive regions of the cell. Taken together, these observations reveal distinct patterns and length scales of RyR and IP3R1 co-clustering at contact sites between the ER and the surface plasmalemma that encode the positions and the quantity of Ca2+ released at each Ca2+ spark.

Influence Mechanism of the Interfacial Water Content on Adhesive Behavior in Calcium Silicate Hydrate−Silicon Dioxide Systems: Molecular Dynamics Simulations

The performance indicators of concrete are mainly determined by the interface characteristics between cement hydration slurry and aggregates. In this study, molecular dynamics technology was used to evaluate the effect of the interfacial water content on the evolution of the interface structure, interaction energy, and mechanical properties of calcium silicate hydrate (C-S-H) and silicon dioxide (SiO2) systems, and the weakening mechanism of the C-S-H/SiO2 interface in a humid environment was revealed. The results showed that all stress–strain curves of C-S-H/SiO2 were divided into the elastic stage and the failure stage. As the interfacial water layer thickened, the molecular weight of the water invading the C-S-H gradually increased, and the desorption of Ca2+ ions in the surface region became significant, while the amount of Ca2+ ions entering the water-layer region increased. The interaction energy of the C-S-H/SiO2 progressively became larger, and the energy ratio (ER) significantly decreased; the tensile strength σc and residual strength σr of C-S-H/SiO2 both showed a downward trend. In summary, a lower water content had a limited impact on the interfacial bonding strength, while the weakening effect enhanced with an increase in the interfacial water content. This phenomenon was also demonstrated in concrete interfacial bond strength experiments.

Effects of calcium ions on the particle performance of luteolin-loaded zein-gum arabic-tea polyphenols ternary complex nanoparticles

Zein-gum arabic-tea polyphenols ternary complex nanoparticles have been developed for the encapsulation of luteolin, but there are still shortages existed in their particle properties such as encapsulation efficiency, stability, and release ability of luteolin. To improve their performance, calcium ions (Ca2+) were employed as a cross-linking stabilizer to investigate their effects on particle properties and functional performance. Particle parameters, physicochemical stability, antioxidant activity, and in vitro simulated gastrointestinal digestion were evaluated based on zetasizer measurement and multi-spectral methods, which were analyzed using Graphpad Prism v6.0.2. As a result, low concentrations of Ca2+ induced the formation of smaller and more compact nanoparticles with improved luteolin encapsulation efficiency, while higher concentrations had the opposite effect. Hydrophobic, electrostatic, and hydrogen bonding interactions were found to be responsible for nanoparticle assembly and stability with Ca2+ incorporation. Appropriate amounts of Ca2+ promoted the physicochemical stability of the nanoparticles under different conditions such as pH, salt ion concentration, temperature, and storage time. Additionally, low levels of Ca2+ strengthened the antioxidant activity of the nanoparticles and improved sustained release of luteolin under in vitro gastrointestinal conditions. These findings suggest that zein-gum arabic-tea polyphenols nanoparticles assembled with Ca2+ have potential applications as a delivery system for bioactive substances.

Osteogenic cell proliferation and antibacterial properties of CaCu–NaTaO3 on biomedical tantalum

Tantalum (Ta) has been utilized used in hard tissue grafts because of its high mechanical strength, excellent corrosion resistance, and biocompatibility. However, due to its low bioactivity, inability to stimulate new bone formation, and lack of antimicrobial activity, its clinical application is limited. Ca2+ can efficiently enhance cell activity and stimulate cell differentiation to form new bone; Cu2+ is an antibacterial ion that is both biologically active and non-resistant at appropriate concentrations. A hydrothermal-molten salt-hydrothermal method was used in this study to create Ca2+ and Cu2+ co-doped NaTaO3. The findings demonstrate that the amount of Ca2+ and Cu2+ doped in the co-doped sample is significantly influenced by the doping sequence and the concentration of Cu2+ solution. The doping sequence of first doping Ca2+ and then doping Cu2+ can further increase the doping amount of the two ions. The change of doping sequence affects the surface morphology, interplanar spacing, and doping concentration. The optimum doping concentration of Ca2+ and Cu2+ in CaCu–NaTaO3 is 3.09 at.% and 2.31 at.%, and the film thickness is about 1.5 μm. ICP, cell, and antibacterial experiments proved that the CaCu–NaTaO3 film has biological and antibacterial activity.

Effects of vitamin B12 in culture medium for calcified nodule formation by rat dental pulp cells

Background/purposeTooth or bone regeneration requires large numbers of mesenchymal stem cells (MSCs). Although dental pulp is a suitable cell source, the number of MSCs present in this tissue is limited and they require a long period for regeneration. Therefore, the present study investigated vitamin B12 (Vb12) as an osteoinductive factor for MSCs obtained from dental pulp. Materials and methodsDental pulp tissue was removed from the root canals of the extracted mandibular incisors of three 6-week-old male Fischer 344/N Slc rats using an endodontic file and whole cells were harvested. After the primary culture, cells were sub-cultured for calcified nodule formation in MEM containing dexamethasone (Dex), β-glycerophosphate (β-GP), vitamin C (Vc), and Vb12. Calcified nodules were confirmed under an inverted phase-contrast microscope. The alkaline phosphatase (ALP) activity of cells and quantity of Ca2+ in calcified nodules were measured. Results were analyzed using the Tukey-Kramer test. ResultsDensely arranged calcified nodules were microscopically observed after the subculture of cells with Dex, β-GP, Vc, and Vb12. The ALP activity level was 0.077 ± 0.023 μmol/μg DNA in MEM supplemented with Vb12, which did not significantly differ from that without Vb12. A mass of calcium nodules formed in culture medium containing Dex, β-GP, Vc, and Vb12. The quantity of Ca2+ increased from 13.04 ± 0.44 to 20.91 ± 0.56 mg/dL (P < 0.01). ConclusionVb12 is effective for in vitro tooth or bone regeneration by the MSCs of rats and is useful as an osteoinductive factor for MSCs.

Effect of a Ca-rich environment on the reaction process of the MgO-activated SiO2 system

The mechanism of the effect of a Ca-rich environment on the reaction process and the molecular structure of the magnesium oxide (MgO)-activated SiO2 reaction product are described in this research. In the experimental study, MgO, silica fume, and calcium oxide (CaO) were used as raw materials to prepare a calcium-magnesium coupling excited SiO2 system with different Ca:Mg molar ratios. The samples were characterized by X-ray diffraction, thermogravimetry/derivative thermogravimetry, inductively coupled plasma mass spectroscopy, transmission electron microscopy, and 29Si nuclear magnetic resonance. A higher Ca:Mg molar ratio (above 0.179:1) inhibited magnesium silicate hydrate gel formation, while a lower ratio (less than 0.09:1) promoted magnesium silicate hydrate gel formation. The amount of Ca2+ and Mg2+ presented in the pore solution in the Ca-rich environment was not sufficient to react with silicate ions (H2SiO2− 4 and H3SiO− 4) to form gel, leading to surplus SiO2. Changes in the Ca2+ concentration in the pore solution affected Mg2+ and silicate ions behavior. The hydration of low amounts of CaO provided ionization products of Ca2+ and OH− ions, MgO and CaO were hydrolyzed, and less ionized OH− was consumed by silicate ions. The hydration and ionization of MgO increased the Mg2+ concentration, while the silicate ions concentration decreased. However, excess OH− ions produced by hydration and ionization with high amounts of CaO exhibited opposite effects, subsequently impacting the calcium–magnesium coupling excited SiO2 system. Thermodynamic calculations revealed that the magnesium silicate hydrate gel was more stable than the calcium silicate hydrate gel, and the influence of various Ca-rich environments on the MgO-activated SiO2 reaction process was further studied.

The Erosion Process Effect on the Physical-Chemical Properties of Grey-Brown Soils in Mountain Shirvan

In the article, the influence of the process of erosion on the physical and chemical properties of soil in Nagorny Shirvan is shown. In non-eroded soils, the main place among cations is occupied by Ca2+cation, Mg2+ cation is much smaller than it, and Na+ is very insignificant. As the degree of erosion increased, the amount of Ca2+cation decreased. No drastic changes were observed in the Mg2+cation. The Na+ cation increased as erosion increased, which in turn leads to soil compaction. The value of pH shows that the alkalinity of the soil actually increased without the development of erosion. This led to some weakening of soil fertility.

Ca doping to enhance energy storage performance of lead‐free SrTi 0.99 Mn 0.01 O 3 thin films with low hysteresis

Dielectric materials with excellent energy storage performance are urgently needed in advanced electrical power systems. We have reported that Mn2+-doped SrTiO3 thin films have high energy storage density. However, the thin films exhibit fat polarization-electric field hysteresis loops with high hysteresis, which is not conducive to greater energy storage performance. In this work, the Ca2+-doped Sr1-xCaxTi0.99Mn0.01O3 thin films are fabricated to construct slim polarization-electric field hysteresis loops with low hysteresis for obtaining excellent energy storage performance. Because Ca2+ can break the long-range ferroelectric order of SrTi0.99Mn0.01O3, the domain size decreases and the coupling of domains weakens, ultimately leading to low hysteresis. Moreover, doping Ca2+ can induce distortion of the octahedral [TiO6] to form local polarization regions. When doped an appropriate amount of Ca2+, local lattice distortion plays an important role in polarization behavior, which helps to enhance polarization. Meanwhile, the Ca2+-doped thin films also possess good insulation. Finally, the higher energy storage density of 63.9 J cm-3 is achieved in the Sr0.9Ca0.1Ti0.99Mn0.01O3 thin film. When the electric field is less than 4000 kV cm-1, the energy storage efficiency remains above 70%. Simultaneously, a wide working temperature range from -100℃ to 100℃ is also obtained.

Pathophysiological role of NNAT in ER+ breast cancer

Neuronatin (NNAT) was recently identified as a novel mediator of estrogen receptor‐positive (ER+) breast cancer cell proliferation and migration, which correlated with decreased tumorigenic potential and prolonged patient survival. However, despite these observations, the molecular and pathophysiological mechanism(s) of NNAT in ER+ breast cancer remain unclear. Based on high protein homology with phospholamban, we hypothesized that NNAT mediates homeostasis of intracellular calcium [Ca2+]i) levels and endoplasmic reticulum (EndoR) function, which is frequently disrupted in ER+ breast cancer and other malignancies.To evaluate the role of NNAT on [Ca2+]i homeostasis, we used intracellular labeling and subcellular confocal imaging of multiple breast cancer models (ER+ breast cancer cell lines T47D and ZR75, MCF10A normal mammary epithelial cells, and MDA‐MB‐231 triple‐negative breast cancer cell lines originally obtained from ATCC (American Type Culture Collection) to better understand the role of NNAT in Ca2+‐mediated cellular functions.Our data indicate that NNAT localizes predominantly to EndoR and lysosome, and genetic manipulation of NNAT levels demonstrated that NNAT modulates [Ca2+]i influx and maintaining Ca2+homeostasis. The application of thapsigargin and consecutive inhibition of SERCA in ER+ breast cancer cells overexpressed NNAT show a significant elevation in the amount of Ca2+ in EndoR (184 ± 5 %, p&lt;0.001 comparing to GFP). At the same time, overexpression of NNAT increased basal cytosolic Ca2+ concentration up to 50% (p&lt;0.001 comparing to GFP). Pharmacological inhibition of calcium channels revealed that NNAT regulates [Ca2+]i levels in breast cancer cells through the interaction with ORAI1 but not the TRPC3 signaling cascade. Furthermore, NNAT transcriptionally regulated by NRF1, PPARα, and PPARγ and is strongly upregulated by oxidative stress via the ROS and PPAR signaling cascades.Collectively, these data suggest that NNAT regulates Ca2+homeostasis in response to oxidative stress, thus providing a molecular link between the longstanding observation that accumulating ROS and altered Ca2+signaling are key oncogenic drivers of cancer.

Micro Raman and XPS surface analysis to understand the electrochemical behaviour of AZ31 and AZ91 magnesium alloys as temporary implant materials.

Degradable metals and alloys have a potential use for surgical orthopedic applications. In this work, surface oxide/hydroxides formed by degradation, are evaluated in two commercial magnesium alloys (AZ31 and AZ91 alloys) by Raman, electrochemical and X-ray spectroscopic techniques. Electrochemical and surface/composition characterization of the AZ31 and AZ91 alloys are developed in contact with Hanks‘ Buffered Salts Solution (HBSS) at 37 °C. AZ31 alloy shows lower corrosion resistance than AZ91 in HBSS at 37 °C, both for short (24 h) and long (17 days) periods of immersion. The surface analysis demonstrate that on both alloys there are abundant corrosion products and the presence of compounds related to apatite. These results show that layers of magnesium oxide and hydroxide can be formed on the alloys surfaces, which gives them a certain degree of protection. The simulated body fluids contain different amounts of Ca2+ ions, carbonates / bicarbonates and phosphates, in addition to the Mg2+ ions (and other cations such as Al3+ and Zn2+) coming from the biomaterial corrosion environment. Thus, specific surface conditions can vary, such as the local pH value, and different corrosion products can precipitate which have different substrate protection properties. These corrosion products can slow down the degradation and influence the adsorption of proteins and cellular adhesion to the Mg surface by changing its chemistry and topography. The use of compositional (Raman and X-ray spectroscopies) and electrochemical (EIS and polarization curves) techniques, allows to do generate advances in the surface and degradation knowledge of typical Magnesium alloys like AZ31 and AZ91, for possible use as temporary implants. Even the analysis was carried out under static conditions, the systematic approach done is complete to picture the degradation mechanism of these alloys. Flow laboratory experiments are consider important to include as future work.

Unveiling significance of Ca2+ ion for start-up of aerobic granular sludge reactor by distinguishing its effects on physicochemical property and bioactivity of sludge

Almost all of the aerobic granular sludge (AGS) reactors were fed on certain amounts of Ca2+ ion, but whether and why it was necessary for reactor start-up remain unknown. Herein, this study conducted a set of comparative experiments in three AGS reactors, which were operated in parallel with Ca2+ addition in R3, hydroxyapatite (HAP) addition in R1, and without any forms of Ca addition in R2. Results showed that R3 not only achieved the complete granulation of sludge, but exhibited superior performance of COD and nutrient removal. In contrast, R1 had a slightly quicker granulation rate than R3 (R1: 0.07 day−1; R3: 0.06 day−1), but the formed granules could not efficiently degrade pollutants. In R2, both sludge granulation and pollutants removal did not proceed normally. Further investigations found that the Ca2+ ion acted in three ways: (1) it increased inorganic composition of sludge to promote granulation; (2) the transformed HAP strengthened stability of granular structure; (3) it ensured bioactivity of granules by driving enrichment of functional microbes and synthesis of metabolism enzymes. Overall, this study systemically proved significance of Ca2+ ion for the start-up of AGS reactors and its influencing mechanisms on different properties of granules.

Effects of iron ion dissolution and migration from phosphorite on the surface properties of dolomite

The partial dissolution of minerals occurs during the production of phosphate ore flotation slurry, producing a certain amount of Ca2+, Mg2+, Fe3+, Al3+, and other metal ions. These metal ions can modify a solution’s chemical environment and the mineral surface properties. Herein, the dissolution and migration behaviors of iron ions in phosphate ore and their effects on the surface properties of dolomite during the flotation slurry process were investigated. Results showed that the maximum Fe3+ content in the slurry was 9.1×10−5 mol/L at pH 5.5. Contact angle and adsorption experiments showed that Fe3+ in the slurry would be adsorbed on the dolomite surface, thus changing its surface properties and reducing the contact angle on the dolomite surface. Results of solution chemistry calculations, zeta potential measurements, and X-ray photoelectron spectroscopic analysis（XPS） indicated the presence of Fe3+ in the slurry in the form of Fe(OH)2+ and FeOH2+, which are adsorbed on the dolomite surface via electrostatic interactions and ultimately reduce the number of adsorption sites of sodium oleate (C18H33NaO2, hereinafter referred to as NaOL). Furthermore, some Fe3+ will react with NaOL to form precipitates of iron oleate, which ultimately reduce the NaOL content in the slurry. Consequently, these two phenomena work to collectively inhibit the hydrophobicity of dolomite in the presence of NaOL.

Effects of intracellular calcium accumulation on proteins encoded by the major genes underlying amyotrophic lateral sclerosis

The aetiology of Amyotrophic Lateral Sclerosis (ALS) is still poorly understood. The discovery of genetic forms of ALS pointed out the mechanisms underlying this pathology, but also showed how complex these mechanisms are. Excitotoxicity is strongly suspected to play a role in ALS pathogenesis. Excitotoxicity is defined as neuron damage due to excessive intake of calcium ions (Ca2+) by the cell. This study aims to find a relationship between the proteins coded by the most relevant genes associated with ALS and intracellular Ca2+ accumulation. In detail, the profile of eight proteins (TDP-43, C9orf72, p62/sequestosome-1, matrin-3, VCP, FUS, SOD1 and profilin-1), was analysed in three different cell types induced to raise their cytoplasmic amount of Ca2+. Intracellular Ca2+ accumulation causes a decrease in the levels of TDP-43, C9orf72, matrin3, VCP, FUS, SOD1 and profilin-1 and an increase in those of p62/sequestosome-1. These events are associated with the proteolytic action of two proteases, calpains and caspases, as well as with the activation of autophagy. Interestingly, Ca2+ appears to both favour and hinder autophagy. Understanding how and why calpain-mediated proteolysis and autophagy, which are physiological processes, become pathological may elucidate the mechanisms responsible for ALS and help discover new therapeutic targets.