Effect Of Different Ions Research Articles

Purification and characterization of fibrinolytic protease from Streptomyces parvulus by polyethylene glycol-phosphate aqueous two-phase system.

Fibrinolytic proteases are a promising alternative in the pharmaceutical industry, they are used in the treatment of cardiovascular diseases, especially thrombosis. Microorganisms are the most interesting source of fibrinolytic proteases. The aim of this study was the production of fibrinolytic protease from Streptomyces parvulus DPUA 1573, the recovery of the protease by aqueous two-phase system and partial biochemical characterization of the enzyme. The aqueous two-phase system was performed according to a 24-full factorial design using polyethylene glycol molar mass, polyethylene glycol concentration, citrate concentration and pH as independent variables. It was analyzed the effect of different ions, surfactants, inhibitors, pH and temperature on enzyme activity. The best conditions for purifying the enzyme were 17.5% polyethylene glycol 8,000, 15% Phosphate and pH 8.0, it was obtained a partition coefficient of 7.33, a yield of 57.49% and a purification factor of 2.10-fold. There was an increase in enzyme activity in the presence of Fe2+ and a decrease in the presence of $\beta$-Mercaptoethanol, phenylmethylsulfonyl fluoride and Iodoacetic acid. The optimum pH was 7.0 and the optimum temperature was 40 ºC. The purified protease exhibited a molecular mass of 41 kDa. The fibrinolytic protease from Streptomyces parvulus proved to be a viable option for the development of a possible drug with fibrinolytic action.

Effects of Ion Characteristics on the Leaching of Weathered Crust Elution-Deposited Rare Earth Ore.

To reveal the ion-exchange mechanism in the leaching process of weathered crust elution-deposited rare earth ores with different leaching agents, the effects of a variety of cations and anions at different concentrations on the leaching process were investigated, including Al3+, Fe3+, Ca2+, Mg2+, Na+, K+, and Cl−, , and . Meanwhile, the relationships between different concentrations of cations and anions and leaching efficiency were investigated, as was the relationship between different concentrations of cations and anions and zeta potential. The effect of different ions on the swelling of clay minerals during leaching process was also investigated. The results shown that was the most affected electrolyte cation in terms of rare earth leaching efficiency during the leaching process of weathered crust elution-deposited rare earth ore among three different cationic valence states, and the leaching efficiency was 86.93% at the optimal leaching concentration. The influence of the three anions on the leaching efficiency of rare earth was , and the leaching efficiency of rare earth were 83.21, 81.52, and 80.12% at the optimal leaching concentration, respectively. The had the greatest effect on the zeta potential of weathered crust elution-deposited rare earth ore, and the zeta potential was −18.1 mV at the optimal leaching concentration. Additionally, the order of the effect of three anions on zeta potential was . Combined with the effect on the rare earth leaching process, anions and cations were considered separately, and and Cl− were selected; the relationship between the rare earth leaching efficiency and zeta potential conforms to the follow equations: :Y = −0.48X2 – 13.51X – 1.58, R2 = 0.98133 and Cl−:Y= −1.22X2 – 17.64X + 23.29, R2 = 0.99010. It was also found in the swelling experiment of the weathered crust elution-deposited rare earth ore that the swelling ratio of clay minerals was the lowest when the cation and anion were and Cl− and the swelling ratios were 1.874 and 2.015%, respectively.

Mechanical and microstructural response of the Al0.5CoCrFeNi high entropy alloy to Si and Ni ion irradiation

The nearly infinite compositional design space of high entropy alloys (HEAs) presents many opportunities to improve performance in extreme environments, particularly for nuclear reactors. The ability of some HEAs to resist high amounts of radiation damage, while well documented, has not yet been fully exploited. We studied the irradiation effect of different ions (Si and Ni) on the microstructure and mechanical properties of the Al0.5CoCrFeNi alloy at its equilibrium state, and of the individual response of each phase to irradiation. The results show a stronger effect of Si ions and differences in response of the ductile FCC (A1) and brittle ordered BCC (B2) phases towards irradiation. This finding highlights the need to further probe unexplored compositional spaces in HEAs, as further optimization is likely to yield further compositional and microstructural stability with practical applications.

Hydrogeochemical and statistical analysis of high fluoride groundwater in northern China.

Understanding the formation of high fluoride (F-) groundwater in water-scarce northern China is critical for the sustainable development of the region. This study investigates the effects of F- enrichment in groundwater from seven typical regions of northern China, including Datong, Guide, Junggar, Yinchuan, Taiyuan, and Tarim basins and the North China Plain. A literature survey of 534 samples of selected regions showed that 45.13% of groundwater F- exceeded the 1.0 mg/L of Chinese drinking water guideline. Based on the geological background and hydrogeochemical analysis, in Datong and Yinchuan basins and part of the North China Plain, the main types of groundwater are soda water and controlling processes of F- enrichment are salinization, mineral dissolution, and desorption. In Taiyuan and Guide basins with Cl-Na water type, F- enrichment is mainly affected by salinization, cation exchange, and evaporation. The hydrogeochemical characteristics of high F- groundwater in Tarim and Junggar basins reflect the extent of salinization and weathering dissolution of minerals in groundwater. According to PCA, the contribution of salinization and mineral dissolution to F- enrichment is relatively high. Under the alkaline condition, groundwater with high Cl-, HCO3-, and Na+ concentration favors F- enrichment. Based on HCA, index clustering category I explains the influence of pH and buried depthon F- enrichment, and category II explains the effect of different ions. It is concluded that F- enrichment in groundwater is related to hydrogeochemical processes and hydrogeological conditions. The hydrogeochemical and alkaline conditions of groundwater are regulated by mineral dissolution, ion exchange, and evaporation, resulting in different degrees of F- enrichment.

Effects of Different Ions and Temperature on Corrosion Behavior of Pure Iron in Anoxic Simulated Groundwater.

As a typical material of the insert in high-level radioactive waste (HLW) geological disposal canisters, iron-based materials will directly contact with groundwater after the failure of a metallic canister, acting as a chemical barrier to prevent HLW leaking into groundwater. In this paper, anoxic groundwater was simulated by mixing 10 mM NaCl and 2 mM NaHCO3 purged by Ar gas (containing 0.3% CO2) with different added ions (Ca2+, CO32− and SiO32−) and operation temperatures (25, 40 and 60 °C). An electrochemical measurement, immersion tests and surface characterization were carried out to study the corrosion behavior of pure iron in the simulated groundwater. The effects of Ca2+ on the corrosion behavior of iron is negligible, however, Cl− plays an important role in accelerating the corrosion activity with the increased concentration and temperature. With increased concentrations of CO32− and SiO32−, the corrosion resistance of iron is largely improved, which is attributed to the formation of a uniform passivation film. The independent effects of temperature on the corrosion behavior of iron are resulted from the repeated passivation–dissolution processes in the formation of the passivation film, resulting from the synergistic effects of CO32−/SiO32− and Cl−. The formation of ferric silicate is dominant in the passivation film with the addition of SiO32−, which effectively protects the iron surface from corrosion.

Enhanced adsorption of nicotinic acid by different types of Mg/Al layered double hydroxides: synthesis, equilibrium, kinetics, and thermodynamics

The aim of this study was to investigate the effect of different ions in the interlayer spaces of layered double hydroxides (LDHs) with different Mg/Al ratios on the adsorption of aqueous nicotinic acid (NAc). For this purpose, three types of LDHs were synthesized for NAc removal using the co-precipitation method with different Mg/Al ratios to include chloride or nitrate anions between the layers (Cl-LDH2:1, NO3-LDH3:1, and NO3-LDH2:1). The LDHs were characterized with Fourier transform infrared spectroscopy, X-ray diffraction, and inductively coupled plasma mass spectrometry, and the effects of initial acid concentration, time, temperature and adsorbent amount on NAc adsorption were investigated. The results showed that the Langmuir equilibrium isotherm model was the best for all three LDHs, and among the kinetic models, the pseudo-second-order agreed the most with experimental data. ΔG, ΔH, and ΔS were calculated for all LDHs, and according to the data, the adsorption of NAc was endothermic and spontaneous. When all the results were evaluated comparatively, it was found that NO3-LDH2:1, with a 2:1Mg/Al ratio and nitrate ions between the layers, has the best NAc adsorption capacity.

Analysis of Cellular Activity Short-Term Exposure to Cobalt and Chromium Ions in Mature Human Osteoblasts.

In aseptic loosening of endoprosthetic implants, metal particles, as well as their corrosion products, have been shown to elicit a biological response. Due to different metal alloy components, the response may vary depending on the nature of the released corrosion product. Our study aimed to compare the biological effects of different ions released from metal alloys. In order to mimic the corrosion products, different metal salts (CoCl2, NiCl2 and CrCl3 × 6H2O) were dissolved and allowed to equilibrate. Human osteoblasts were incubated with concentrations of 10 µM to 500 µM metal salt solutions under cell culture conditions, whereas untreated cells served as negative controls. Cells exposed to CoCr28Mo6 particles served as positive controls. The cell activity and expression of osteogenic differentiation and pro-osteolytic mediators were determined. Osteoblastic activity revealed concentration- and material-dependent influences. Collagen 1 synthesis was reduced after treatment with Co(2+) and Ni(2+). Additionally, exposure to these ions (500 µM) resulted in significantly reduced OPG protein synthesis, whereas RANKL as well as IL-6 and IL-8 secretion were increased. TLR4 mRNA was significantly induced by Co(2+) and CoCr28Mo6 particles. The results demonstrate the pro-osteolytic capacity of metal ions in osteoblasts. Compared to CoCr28Mo6 particles, the results indicated that metal ions intervene much earlier in inflammatory processes.

PHOTOCATALYTIC PROPERTY AND PHOTOCATALYTIC MECHANISM OF TiO2/Fe2O3 HYBRIDS FOR DEGRADATION OF ORGANIC DYES

In order to consider the performance enhancement and feasibility of practical application, this research work discussed the effects of different ions on the photocatalytic activity of TiO2/Fe2O3 hybrids in detail, involving H[Formula: see text], OH−, NH[Formula: see text], and NO[Formula: see text]. The TiO2/Fe2O3 hybrids were prepared by organic electrolyte-assisted sol–gel method under UV irradiation, and their function mechanisms were analyzed. Experiment results show that the resultant TiO2/Fe2O3 hybrids possess excellent photocatalytic activity and photocatalytic stability for degradation of organics under acid condition (pH 2–8). Notably, the NO[Formula: see text] ions could accelerate degradation of rhodamine B and methyl orange, and the recyclability of TiO2/Fe2O3 hybrids can be greatly enhanced in the co-existence of NO[Formula: see text] and NH[Formula: see text]. Meanwhile, this symbiosis of NO[Formula: see text] and NH[Formula: see text] is proven able to buffer the solution pH in photocatalysis. Furthermore, the prominent photocatalytic activity of TiO2/Fe2O3 hybrids for organic pollutants was mainly attributed to the formation of hydroxyl radicals (OH). The synthetic products show great potential applications in purification of air or wastewater that contains ammonia-nitrogen molecules.

Optimization of Vapor Diffusion Conditions for Anti-CD20 Crystallization and Scale-Up to Meso Batch

The crystal form is one of the preferred formulations for biotherapeutics, especially thanks to its ability to ensure high stability of the active ingredient. In addition, crystallization allows the recovery of a very pure drug, thus facilitating the manufacturing process. However, in many cases, crystallization is not trivial, and other formulations, such as the concentrate solution, represent the only choice. This is the case of anti-cluster of differentiation 20 (anti-CD20), which is one of the most sold antibodies for therapeutic uses. Here, we propose a set of optimized crystallization conditions for producing anti-CD20 needle-shaped crystals within 24 h in a very reproducible manner with high yield. High crystallization yield was obtained with high reproducibility using both hanging drop vapor diffusion and meso batch, which is a major step forward toward further scaling up the crystallization of anti-CD20. The influence of anti-CD20 storage conditions and the effect of different ions on the crystallization processes were also assessed. The crystal quality and the high yield allowed the first crystallographic investigation on anti-CD20, which positively confirmed the presence of the antibody in the crystals.

Effect of Different Ions on Bentonite Minerals

Bentonite is widely used as backfill material for radioactive waste disposal as a natural mineral with high efficiency, stability and low cost. Since the safety evaluation time system of radioactive waste repositories lasts for ten thousand years, the mineral evolution of bentonite after ten thousand years and its effects on the adsorption and retardation properties of Pu are the key points of attention. In this paper, the mineral composition and porosity change of Ke Er Jian bentonite with five Na+/Ca2+/Al3+/K+/Mg2+ ion species in ten thousand year scale were simulated by PHREEQC(3.0) software, the changes of bentonite minerals and their effects on the adsorption properties of nuclide Pu were discussed from two aspects of groundwater transport distance and interaction time, which provided important reference for the safety evaluation of waste disposal.

Effect of different ions present in fresh water on performance of polyvinylamine based ASA emulsion

Alkenyl succinic anhydride (ASA) is an alkaline sizing chemical used during papermaking. ASA emulsified in conventionally used cationic starch (CS) solution, has low shelf life i.e. 20–25 minutes and forms stickies/deposits as a result of hydrolyzed ASA on paper machine wire. Anionic polyvinylamine (APVAm) dilution in de-ionized water as a substitute to CS for ASA emulsification is a protective colloid, which seems to provide a protective shield to the ASA molecules, thereby reducing hydrolysis. In that case, the ASA emulsion was found to be stable up to four hours. In our knowledge no reliable studies have been done on study of different ions present in fresh water used for the preparation of APVAm stabilized ASA emulsion for commercial utilization. The present communication relates to the study on effect of different ions viz. Ca2+, Mg2+, Cl−, SO42− & HCO3− present in fresh water on the performance of ASA emulsion prepared by using APVAm as protective colloid. The permissible limit of each ion was measured. It was observed that the concentration of calcium ions was higher than the maximum permissible limit which may be responsible for the poor emululsification of ASA. The concentrations of Mg2+ ions and other counter ions were less than that of the maximum allowable limit. It was also observed that chloride ions adversely affected while bicarbonate ions assisted the ASA emulsification.

Analytical application of the reaction system disulphonated hydroquinone-hydrogen peroxide for the kinetic spectrophotometric determination of iron traces in acidic media

A simple, rapid, sensitive and selective kinetic spectrophotometric method for determination of Fe(III) traces was elaborated in this paper. It is based on the catalytic effect of Fe(III) ions on oxidation of potassium salt of disulphonated hydroquinone (K2S2Hy) by hydrogen peroxide in acidic media, at a constant ionic strength. At the working temperature of 20?C and the wavelength of 450.0 nm, optimal conditions for determination of iron were found so that iron (III) can be determined by the proposed method in the concentration range of 1.87 to 18.7 ng cm-3. Corresponding RSD values were determined to be in the range 4.22 to 10.33 %. The limit of detection (LOD) calculated in two ways was found to be 1.07 ng cm-3 i.e. 1.11 ng cm-3 Fe(III). In order to assess the selectivity of the method effects of different ions on the reaction rate were also determined. It was found that presence of oxalates and citrates in the w/w ratio to Fe(III) 1:1 under selected experimental conditions interferes with determination of iron. Then the method was applied for determination of Fe(III) traces in white radish juice. The results agreed well with those obtained by atomic absorption spectrometry.

Adsorption of Quinolone Antibiotics to Goethite under Seawater Conditions: Application of a Surface Complexation Model.

The assessment of antibiotics mobility under seawater conditions has been rarely studied, as an accurate description of such multicomponent systems is quite challenging. In this study, the adsorption of a widely used quinolone antibiotic in aquaculture, Oxolinic acid (OA), to a synthetic goethite (α-FeOOH) was examined in the presence of major (e.g., Mg2+, SO42-) and trace (e.g., Cu2+) ions naturally occurring in seawater. The OA adsorption can be successfully predicted using a charge distribution multisite complexation model (CD-MUSIC) coupled with the three plane model (TPM). This modeling approach allowed a quantification of the competitive and synergetic effects of different ions in seawater over a large range of environmentally relevant conditions. In addition, the transport of OA in flow-through columns can be well predicted through coupling hydrodynamic parameters and surface complexation constants obtained under seawater conditions. These results may have strong implications for assessment and prediction of the fate of quinolones in sediment-seawater interface systems.

Effects of ion species on the disinfection byproduct formation in artificial and real water

Disinfection byproducts (DBPs) have attracted extensive attention due to their cytotoxicity and genotoxicity. This study investigates the effects of different ions on DBP formation during chlorination and chloramination in artificial and real water samples. Compared with chlorination, chloramination can reduce the formation of DBPs. K+ only reduce the formation of DBPs during chloramination. Ca2+ forms less DBPs than Mg2+ does during chlorination and chloramination due to the stronger binding effect. Al3+ and their hydroxide colloids have a significant effect on DBP formation. Anions have no significant effect on DBP formation. Due to the difference between the real and artificial water samples, the large amount of NH4+ in the real water will form chloramine during chlorination. Furthermore, the effects of different ion in the chlorination will have the same tendency during chlorination. In the wastewater with high ionic strength, the effects of salts are mostly ignored. Studying the effects of different ions on DBP formation is important in controlling the content of DBPs in the disinfection process.

The Corrosion Behavior of AZ91D Magnesium Alloy in Simulated Haze Aqueous Solution

The corrosion process of AZ91D magnesium alloy in simulated haze aqueous solution has been studied by electrochemical measurements, immersion tests and morphology characterization. Results show that AZ91D was corroded heavily in simulated haze aqueous solution due to the loose and breakable product film on the surface providing little corrosion barrier. The effect of different ions was investigated. It was found that both and played an important role in the corrosion process. helped to form passive film to protect the matrix, yet consumed OH−, resulting in the absence of Mg(OH)2 and serious corrosion. Meanwhile, and Cl− had influence on pitting corrosion. Magnesium aluminum oxide and MgAl2(SO4)4·22H2O instead of Mg(OH)2 were the dominate products, which is different from the former study. Corrosion rate changed with time, especially in the first 3 h. A two-stage corrosion mechanism is proposed after considering both the corrosion process and the influence of ions.

Effect of organic and inorganic ions on the lower critical solution transition and aggregation of PNIPAM.

We have studied the effect of different ions belonging to the extended Hofmeister series on the thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAM), by combining Differential Scanning Calorimetry (DSC) and Dynamic Light Scattering (DLS). The variations in the lower critical solution temperature (TLCS) and enthalpy change during PNIPAM phase separation evidence the importance of considering both hydration and hydrophobicity to explain the interaction of ions with interfaces. The results obtained in the presence of inorganic ions can be explained by the tendency of water molecules to preferentially hydrate the PNIPAM chains or the ions, depending on the kosmotropic (highly hydrated) or chaotropic (poorly hydrated) character of the ions. On the contrary, tetraphenyl organic ions (Ph4B- and Ph4As+) interact with the hydrophobic moieties of PNIPAM chains, inducing a significant reduction of the TLCS. DLS results show that the aggregation state of PNIPAM above the TLCS is also strongly influenced by the presence of ions. While macroscopic phase separation (formation of a polymer-rich phase insoluble in water) was apparent in the presence of inorganic ions, we observed the formation of submicron PNIPAM aggregates at temperatures above the TLCS in the presence of the hydrophobic ions. Kinetically arrested monodisperse PNIPAM nanoparticles were formed in the presence of the Ph4B- anion, while a rather polydisperse distribution of particle sizes was observed in the presence of Ph4As+. These results show that ionic specificity influences both the static (thermodynamic) and dynamic (kinetically controlled aggregation) states of PNIPAM in an aqueous environment.

Effect of ion concentration on the temperature measurement model of extracellular fluid by near-infrared spectroscopy

The temperature of extracellular fluid is a significant characteristic for electrophysiological experiments of patch clamp. It is important to understood the factors affecting the temperature measurement of an extracellular fluid, such as the effect of the concentration of different ions. In this study, the effect of different ions at different concentrations in a small amount of physiological solution on the measurement accuracy of a temperature model was investigated by near-infrared spectroscopy and chemometrics. The interval partial least squares method was used to select an effective wavelength range and develop calibration models using the spectra in the selected range and temperature values. The results indicate that Ca2+ has the greatest effect on the measurement accuracy of the temperature model of a cell physiological solution, followed by K+, and Na+ has the least effect. Moreover, the results indicate that the model accuracy decreased with the increase in ion concentration. These findings provide a basis for correcting the effects of different ion concentrations in a physiological solution for improving the accuracy of temperature measurements by near-infrared spectroscopy.

The Effect of Divalent Metal Ions and Recycle Ratio of UASB Reactor on the Formation of Anammox Granules and Its Treatment Performance

The setting-up of anammox granules reactor is time-consuming and highly sensitive to the environment. Metal ions were reported to facilitate granulation; however, there is no report of a practical guide to metal ion application in anammox, especially relative to the effects of different ions at different concentrations on granulation. Adding recycle to reactors is important in treating industrial wastewater with high levels of NH4 +-N, but the optimum recycle ratio is still unclear. This study investigated the effect of Ca, Mg, Fe ions, their concentration, and recycle ratio of an upflow anaerobic sludge blanket reactor on anammox granulation as well as on reactor performance. The main physical properties of granules tested were sludge granulation rate, settling velocity, mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids/MLSS, and specific anammox activity (SAA)/nitrogen removal rate. The results demonstrated that introducing cations into cultivating mediums accelerates the anaerobic granulation process and improves specific anammox activity. In particular, Mg and Fe runs reached maximum SAAs with concentrations of 0.06 mmol/L and improved by ~ 25% of SAA compared with the control. SAAs of Ca runs were lower than those of Mg and Fe runs and showed a peak at a concentration of 0.03 mmol/L. In addition, recirculation enhanced the granulation. Granulation and retention of the anammox biomass were benefitted most when the recycle flow added was equal to the influent injection (noted as Q). Nitrogen removal also reached a maximum at Q, with removal efficiency of 97.3% with NH4 +-N and 98% with NO2 −-N. Thus, appropriately adding metal ions and recycle flow helped achieve quick setting-up and better performance. We also considered the relationship between four properties of granules tested and the performance of the reactor.

Characterization of protease activity from the digestive tract and tentacles of Isostichopus fuscus sea cucumber

Sea cucumbers possess evisceration mechanisms and regeneration capacity. The function of tentacles is to collect food particles. From our results, we suggest these organs could also be part of the digestive system. Therefore proteases in the digestive tract and tentacles of Isostichopus fuscus were partially characterized by histological and biochemical methods. Digestive cells and regions, and secretory granules were observed by histological methods in both organs. Proteolytic extracts of the digestive tract and tentacles showed peak activity at pH 6 and 8. The digestive tract extract had peak activity at 40 and 70 °C, whereas the tentacle extract peak activity was at 60 °C. Both extracts showed activity at 0 to 10 °C. The extracts retained 67 to 75 % residual activity when incubated at 60 °C for 1 h. The effect of different ions and specific inhibitors suggested the presence of cysteine- and metallo-proteases in both organs. SDS-PAGE showed 6 proteins of approximately 40, 43, 49, 76, 106, and 147 kDa in the digestive tract extract, and 5 proteins of approximately 44, 60, 81, 108, and 150 kDa in the tentacle extract. Native-PAGE and zymography assays confirmed the presence approximately 100 kDa proteases in both extracts. The tentacle extract had the highest proteolytic activity, suggesting that this organ could contribute to the digestion process of I. fuscus. Key Words: ; ; ; ;

Degradation of Magnesium-Rich Primers over AA2024-T3 During Constant Immersion in Different Solutions

Degradation of Mg-rich primer (MgRP) during constant immersion in 1 wt% NaCl solution and in dilute Harrison’s solution was compared. The effects of different ions, Mg pigment connection modes, and...