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[Display omitted] The citric acid modification produces an intermediate layer on the AB-17-8:C 6 H 8 O 7 surface; the layer, on one hand, is firmly secured to the surface owing to the electrostatic coupling between the citrate anion and the positively charged trimethylammonium centers of the anion exchanger surface; on the other hand, it has carbonyl groups with a local negative electron density. The sorption of heavy metals cations occurs through coordination interactions via electrostatic mechanism with local centers of negative electron density, in particular, with the carbonylic oxygen atom. [ABSTRACT FROM AUTHOR]

Solute carrier family 26 member 4 (SLC26A4) is a member of the SLC26A transporter family and is expressed in various tissues, including the airway epithelium, kidney, thyroid, and tumors. It transports various ions, including bicarbonate, chloride, iodine, and oxalate. As a multiple-ion transporter, SLC26A4 is involved in the maintenance of hearing function, renal function, blood pressure, and hormone and pH regulation. In this review, we have summarized the various functions of SLC26A4 in multiple tissues and organs. Moreover, the relationships between SLC26A4 and other channels, such as cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and sodium chloride cotransporter, are highlighted. Although the modulation of SLC26A4 is critical for recovery from malfunctions of various organs, development of specific inducers or agonists of SLC26A4 remains challenging. This review contributes to providing a better understanding of the role of SLC26A4 and development of therapeutic approaches for the SLC26A4-associated hearing loss and SLC26A4-related dysfunction of various organs. [ABSTRACT FROM AUTHOR]

Humic substances (HSs) present in water and wastewater cause fouling of anion exchange resins (AERs), which mainly results in reducing the ion exchange capacity (IEC). In this paper, an attempt was made to investigate fouling of two polystyrene and one polyacrylic AER using water from the Oder River, treated wastewater after the ultrafiltration process (UFTW) and digester reject water from sludge dewatering at the Janówek Wastewater Treatment Plant (WWTP) in Wrocław. HSs contained in digester reject water were characterised by the lowest aromaticity and molecular weights (MWs), the highest proportion of hydrophilic fraction and the highest amount of oxygenated functional groups. The Fourier-transform infrared (FTIR) analyses made it possible to identify chemical bonds characteristic of HSs and determine the mechanism of their retention on the surface of AER beads. The conducted experiments brought unexpected results, as the IEC increased with the amount of organic matter in the feed. Presumably, the humic substances accumulated on the beads and in the porosity of the anion exchangers themselves participated in the ion exchange process. [ABSTRACT FROM AUTHOR]

Solute carrier family 26 member 4 (SLC26A4) is a member of the SLC26A transporter family and is expressed in various tissues, including the airway epithelium, kidney, thyroid, and tumors. It transports various ions, including bicarbonate, chloride, iodine, and oxalate. As a multiple-ion transporter, SLC26A4 is involved in the maintenance of hearing function, renal function, blood pressure, and hormone and pH regulation. In this review, we have summarized the various functions of SLC26A4 in multiple tissues and organs. Moreover, the relationships between SLC26A4 and other channels, such as cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and sodium chloride cotransporter, are highlighted. Although the modulation of SLC26A4 is critical for recovery from malfunctions of various organs, development of specific inducers or agonists of SLC26A4 remains challenging. This review contributes to providing a better understanding of the role of SLC26A4 and development of therapeutic approaches for the SLC26A4-associated hearing loss and SLC26A4-related dysfunction of various organs.

Humic substances (HSs) present in water and wastewater cause fouling of anion exchange resins (AERs), which mainly results in reducing the ion exchange capacity (IEC). In this paper, an attempt was made to investigate fouling of two polystyrene and one polyacrylic AER using water from the Oder River, treated wastewater after the ultrafiltration process (UFTW) and digester reject water from sludge dewatering at the Janówek Wastewater Treatment Plant (WWTP) in Wrocław. HSs contained in digester reject water were characterised by the lowest aromaticity and molecular weights (MWs), the highest proportion of hydrophilic fraction and the highest amount of oxygenated functional groups. The Fourier-transform infrared (FTIR) analyses made it possible to identify chemical bonds characteristic of HSs and determine the mechanism of their retention on the surface of AER beads. The conducted experiments brought unexpected results, as the IEC increased with the amount of organic matter in the feed. Presumably, the humic substances accumulated on the beads and in the porosity of the anion exchangers themselves participated in the ion exchange process.

Magnetic nickel ferrite/gold hybrid nanoparticles are promising materials for use in medicine, microelectronics, and plasmon-enhanced photocatalysis. The catalytic activity of a hybrid material depends on the composition, morphology, surface charge, and size of the magnetic core. In this work, anion-exchange resin coprecipitation of iron and nickel followed by heat treatment of the prepared hydroxides was used to manufacture nickel ferrite NiFe2O4 nanopowders. Fractional factorial design (FFD 27-4) was used to study the effects of reaction parameters on NiFe2O4 formation. The synthesis under the found optimal conditions yielded powders with an average grain size of 22.7 ± 1.0 nm. NiFe2O4/Au hybrid particles were manufactured by the direct reduction of gold with methionine (α-amino-γ-methylthiobutyric acid). Their formation was proved by optical spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

Direct dyes are still widely used for coloring a variety of materials due to their ease of use and the wide range of colors available at a moderate cost of production. In the aquatic environment, some direct dyes, especially the azo type and their biotransformation products, are toxic, carcinogenic and mutagenic. Hence the need for their careful removal from industrial effluents. It was proposed adsorptive retention of C.I. Direct Red 23 (DR23), C.I. Direct Orange 26 (DO26) and C.I. Direct Black 22 (DB22) from effluents using anion exchange resin of tertiary amine functionalities Amberlyst A21 (A21). Applying the Langmuir isotherm model, the monolayer capacities were calculated as 285.6 mg/g for DO26 and 271.1 mg/g for DO23. The Freundlich isotherm model seems to be the better one for the description of DB22 uptake by A21, and the isotherm constant was found to be 0.609 mg1−1/n L1/n/g. The kinetic parameters revealed that the pseudo-second-order model could be used for the description of experimental data rather than the pseudo-first-order model or intraparticle diffusion model. The dye adsorption decreased in the presence of anionic and non-ionic surfactants, while their uptake was enhanced in the presence of Na2SO4 and Na2CO3. Regeneration of the A21 resin was difficult; a slight increase in its efficiency was observed using 1M HCl, 1 M NaOH and 1 M NaCl solutions in 50% v/v methanol. [ABSTRACT FROM AUTHOR]

[Display omitted] Phosphorus (P) control has been recognized as an imperative task to mitigate water eutrophication and settle the imminent shortage of P resources. Despite intensive effort put into this matter, it is still generally challenging for the current methods to remove and even potentially recover phosphorus (as phosphate) from complicated water matrices. To this end, we proposed a novel nanocomposite via coupling polystyrene anion exchanger (PsAX) with hydrated neodymium oxide (HNdO) nanoparticle for selective removal of phosphate. The developed nanocomposite, i.e., HNdO-PsAX, exhibited quite stable and efficient phosphate adsorption over a wide pH range of 3.0–10.0 with the maximum adsorption capacity as 85.4 mg P/g. It also showed satisfied anti-interference against various competing substances; notably, HNdO-PsAX obviously outperformed Phoslock, a commercial lanthanum-based adsorbent exclusively for phosphate sequestration, particularly under the interference of bicarbonate and humic acid, which were admitted as the paralyzing factors for Phoslock. The superior affinity of HNdO-PsAX towards phosphate, driven by the specific Nd-P inner-sphere complexation as evidenced by XPS, FT-IR, and the lattice evolution of HNdO nanoparticle, renders the nanocomposite eminently suitable for sequestrating trace phosphate. Fixed-bed treatment validated that HNdO-PsAX was capable of treating ∼11,800 bed volume of a simulated wastewater (from 2.0 to below 0.5 mg P/L), approximately 12 times higher than that of the previously reported Fe-based nanocomposite (HFO-PsAX, ∼ 900 BV); also, a satisfactory outcome in treating authentic municipal wastewater by HNdO-PsAX and the feasibility of regenerating the exhausted one by a binary NaOH-NaCl solution were recognized. This work provides a new potion of enhanced phosphorous control for surface water and wastewater. [ABSTRACT FROM AUTHOR]

The reaction of pyridine with cyanuric chloride was studied under microwave activation as well as in the presence of silver nitrate. The product of hydrolysis containing two pyridinium rings and chloride anion was isolated. The structures of these anion exchanger salts with chloride, nitrate and perrhenate anions are discussed. [ABSTRACT FROM AUTHOR]

A strong anion exchanger applied for ion chromatography is described by grafting methacrylamido propyl trimethyl ammonium chloride onto hydrolyzed poly(glycidyl methacrylate‐divinylbenzene) substrate. The anion exchanger has been in detail characterized and the final capacity of the anion exchanger can be readily manipulated by different monomer amounts. It exhibited obvious temperature‐sensitive properties and large tolerance to the samples with high ionic strength. The obtained anion exchanger demonstrated effective separation ability towards the common seven inorganic anions within 12 min and high separation efficiency, for example, 58 000/m of theoretical plate count for chloride. [ABSTRACT FROM AUTHOR]

Direct dyes are still widely used for coloring a variety of materials due to their ease of use and the wide range of colors available at a moderate cost of production. In the aquatic environment, some direct dyes, especially the azo type and their biotransformation products, are toxic, carcinogenic and mutagenic. Hence the need for their careful removal from industrial effluents. It was proposed adsorptive retention of C.I. Direct Red 23 (DR23), C.I. Direct Orange 26 (DO26) and C.I. Direct Black 22 (DB22) from effluents using anion exchange resin of tertiary amine functionalities Amberlyst A21 (A21). Applying the Langmuir isotherm model, the monolayer capacities were calculated as 285.6 mg/g for DO26 and 271.1 mg/g for DO23. The Freundlich isotherm model seems to be the better one for the description of DB22 uptake by A21, and the isotherm constant was found to be 0.609 mg1−1/n L1/n/g. The kinetic parameters revealed that the pseudo-second-order model could be used for the description of experimental data rather than the pseudo-first-order model or intraparticle diffusion model. The dye adsorption decreased in the presence of anionic and non-ionic surfactants, while their uptake was enhanced in the presence of Na2SO4 and Na2CO3. Regeneration of the A21 resin was difficult; a slight increase in its efficiency was observed using 1M HCl, 1 M NaOH and 1 M NaCl solutions in 50% v/v methanol.

Crosslinkers are indispensable constituents for the preparation of SPE materials with ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) among the most prominent representatives. A crosslinker that has not yet been used for the preparation of SPE sorbents is 3,3'-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide [C6-bis-VIM] [Br]. In this study, we synthesized differently crosslinked vinylimidazole polymers with EGDMA, DVB and [C6-bis-VIM] [Br] and evaluated their extraction efficiencies towards phenolic acids. Dispersive SPE experiments performed with the [C6-bis-VIM] [Br] crosslinked polymers exhibited significantly higher extraction recoveries for the majority of analytes. Due to these promising results, the [C6-bis-VIM] [Br] crosslinked polymer was optimized in terms of the monomer to crosslinker ratio and an efficient dispersive SPE protocol was developed, with maximum recoveries ranging from 84.1–92.5% and RSD values ˂ 1%. The developed extraction procedure was also applied to cartridges resulting in recoveries between 97.2 and 98.5%, which were on average 5% higher than with the commercial anion exchange sorbent Oasis® MAX. Furthermore, the sorbent was regenerated showing a good reusability for the majority of analytes. In conclusion, this study clearly highlights the yet untapped potential of the crosslinker, [C6-bis-VIM] [Br], with respect to the synthesis of efficient anion exchange polymers for SPE. [ABSTRACT FROM AUTHOR]

The current investigation highlights the synthesis of adsorption device MHa-g-poly(AN)-AE by graft copolymerization of acrylonitrile (AN) onto Holarrhena antidysenterica fiber in the presence of air along with Ferrous ammonium sulfate (FAS) and Potassium persulfate (KPS) initiators followed by quaternization process. Synthesized samples and backbone were studied using different techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopic (XRD) and TGA/DTA/DTG studies. High efficiency of dye adsorption (99% of malachite green dye) was achieved using an initial dye concentration of 10.0 mg L−1 with an adsorbent dose of 500 mg 50 ml−1 within the time duration of 165 min at neutral pH and 25 °C. Adsorption data best fit with Langmuir Isotherm, pseudo second-order kinetics model and follow both macro & micro-pore intra-particle diffusion.

Rare-earth ferrite garnets (REFGs) have pronounced magnetic and optical properties and are widely used in magnetooptics, laser and microwave technologies. This work offers a method for producing Yb3Fe5O12 powders with a mean grain size of 47 ± 9 nm, by means of the anion-exchange resin coprecipitation of iron(III) and ytterbium followed by annealing of the product at 1100°C. The anion-exchange resin precipitation rate and optimal parameters have been determined, as well as the parameters of precursors heat treatment. The products have been characterized by chemical analysis, X-ray powder diffraction, differential scanning calorimetry, and electron microscopy. The method is promising for the production of other REFGs and nonferrous metal ferrites. [ABSTRACT FROM AUTHOR]

The reaction of pyridine with cyanuric chloride was studied under microwave activation as well as in the presence of silver nitrate. The product of hydrolysis containing two pyridinium rings and chloride anion was isolated. The structures of these anion exchanger salts with chloride, nitrate and perrhenate anions are discussed.

The energy of interaction between various amino acids (glycine, alanine, and phenylalanine) and an AV-17 strongly basic anion exchanger in chloride and nitrate ionic forms under nonexchange absorption conditions is assessed by quantum chemistry calculations. We found that the amount of water in the starting fragments of sorption participants, the counterion of the anion exchanger, and the amino acid radical play an important role in energy and in the ratio of different intermolecular interactions (Coulomb, hydrophobic, and hydrogen bonds) to form ion-molecular structures in the ion-exchanger phase. [ABSTRACT FROM AUTHOR]

Crosslinkers are indispensable constituents for the preparation of SPE materials with ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) among the most prominent representatives. A crosslinker that has not yet been used for the preparation of SPE sorbents is 3,3’-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide [C6-bis-VIM] [Br]. In this study, we synthesized differently crosslinked vinylimidazole polymers with EGDMA, DVB and [C6-bis-VIM] [Br] and evaluated their extraction efficiencies towards phenolic acids. Dispersive SPE experiments performed with the [C6-bis-VIM] [Br] crosslinked polymers exhibited significantly higher extraction recoveries for the majority of analytes. Due to these promising results, the [C6-bis-VIM] [Br] crosslinked polymer was optimized in terms of the monomer to crosslinker ratio and an efficient dispersive SPE protocol was developed, with maximum recoveries ranging from 84.1–92.5% and RSD values ˂ 1%. The developed extraction procedure was also applied to cartridges resulting in recoveries between 97.2 and 98.5%, which were on average 5% higher than with the commercial anion exchange sorbent Oasis® MAX. Furthermore, the sorbent was regenerated showing a good reusability for the majority of analytes. In conclusion, this study clearly highlights the yet untapped potential of the crosslinker, [C6-bis-VIM] [Br], with respect to the synthesis of efficient anion exchange polymers for SPE.

Intensive development of many industries, including textile, paper or plastic, which consume large amounts of water and generate huge amounts of wastewater-containing toxic dyes, contribute to pollution of the aquatic environment. Among many known methods of wastewater treatment, adsorption techniques are considered the most effective. In the present study, the weakly basic anion exchangers such as Amberlyst A21, Amberlyst A23 and Amberlyst A24 of the polystyrene, phenol-formaldehyde and polyacrylic matrices were used for C.I. Direct Yellow 50 removal from aqueous solutions. The equilibrium adsorption data were well fitted to the Langmuir adsorption isotherm. Kinetic studies were described by the pseudo-second order model. The pseudo-second order rate constants were in the range of 0.0609–0.0128 g/mg·min for Amberlyst A24, 0.0038–0.0015 g/mg·min for Amberlyst A21 and 1.1945–0.0032 g/mg·min for Amberlyst A23, and decreased with the increasing initial concentration of dye from 100–500 mg/L, respectively. There were observed auxiliaries (Na2CO3, Na2SO4, anionic and non-ionic surfactants) impact on the dye uptake. The polyacrylic resin Amberlyst A24 can be promising sorbent for C.I. Direct Yellow 50 removal as it is able to uptake 666.5 mg/g of the dye compared to the phenol-formaldehyde Amberlyst A23 which has a 284.3 mg/g capacity. [ABSTRACT FROM AUTHOR]

The current investigation highlights the synthesis of adsorption device MHa-g-poly(AN)-AE by graft copolymerization of acrylonitrile (AN) onto Holarrhena antidysenterica fiber in the presence of air along with Ferrous ammonium sulfate (FAS) and Potassium persulfate (KPS) initiators followed by quaternization process. Synthesized samples and backbone were studied using different techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopic (XRD) and TGA/DTA/DTG studies. High efficiency of dye adsorption (99% of malachite green dye) was achieved using an initial dye concentration of 10.0 mg L−1 with an adsorbent dose of 500 mg 50 ml−1 within the time duration of 165 min at neutral pH and 25 °C. Adsorption data best fit with Langmuir Isotherm, pseudo second-order kinetics model and follow both macro & micro-pore intra-particle diffusion. [ABSTRACT FROM AUTHOR]

During amelogenesis, extracellular matrix proteins interact with growing hydroxyapatite crystals to create one of the most architecturally complex biological tissues. The process of enamel formation is a unique biomineralizing system characterized first by an increase in crystallite length during the secretory phase of amelogenesis, followed by a vast increase in crystallite width and thickness in the later maturation phase when organic complexes are enzymatically removed. Crystal growth is modulated by changes in the pH of the enamel microenvironment that is critical for proper enamel biomineralization. Whereas the genetic bases for most abnormal enamel phenotypes (amelogenesis imperfecta) are generally associated with mutations to enamel matrix specific genes, mutations to genes involved in pH regulation may result in severely affected enamel structure, highlighting the importance of pH regulation for normal enamel development. This review summarizes the intra- and extracellular mechanisms employed by the enamel-forming cells, ameloblasts, to maintain pH homeostasis and, also, discusses the enamel phenotypes associated with disruptions to genes involved in pH regulation.

The study on removal of fluoride from water is performed by using two anion exchangers and two modified cation exchangers by varying contact time, resin dosage, pH, and initial concentration of fluoride ions. Maximum fluoride removal is possible in the pH range of 4.0-10.0 and removal efficiency reaches maximum, within 60 min for anion exchangers and 120 min for cation exchangers. Among Langmuir and Freundlich isotherms, adsorption data fit well in Freundlich isotherm. The kinetic study suggests adsorption process follows pseudo-second-order reaction kinetics. Among two anion exchangers used for the removal of fluoride Tulsion A-10X (MP) has better fluoride removal efficiency than Amberlyst A-21(MP). However, in the case of modified cation exchangers, Al+3 forms of resins have better fluoride removal efficiency than Fe+3 forms. It clearly indicates that modified resins can be useful for the removal of fluoride. Desorption study is also carried out on all the resins using 0.1 N NaOH and 0.1 N HCl. [ABSTRACT FROM AUTHOR]

Sulfates can be removed from seawater by weak base anion exchanger which is regenerated with concentrated potassium chloride solution. The potassium sulfate was removed from the regeneration solution by adding solid KCl, which reduced the solubility of K2SO4 causing its precipitation. Dilution of the regenerated solution was substantially reduced by using three displacement solutions with different KCl concentrations. Precipitation of potassium sulfate in the column during regeneration was prevented by heating the regeneration solution to 55°C. After the regeneration solution exited the column, it was cooled to achieve maximum precipitation of the K2SO4. The weight of the K2SO4 obtained was about the same as that of the KCl used for regeneration. The concentration of sulfate in seawater was reduced from 34 mM to less than 15 mM. To produce one ton of potassium sulfate about 250 tons of seawater is needed. The volume of the solution disposed of to the drain approached zero. [ABSTRACT FROM AUTHOR]

The process of sorption of Zn (II) and Cr (III) ions into PPE-1 anion exchange resin and PPE-1-P polyampholyte containing amine and phosphite group preservatives, obtained on the basis of local raw materials, was studied in artificial solutions under static conditions. Factors that influence the sorption process, namely time dependence, temperature effect, concentration dependence, were studied. The process of sorption of metal ions into ion exchangers was studied in the Pseudo-First-Order and Pseudo-Second-Order kinetic models, and it was determined by studying the absorption kinetics that the sorption process was the Pseudo-Second-Order Kinetic Model. The Langmuir and Freundlich constants of the isotherm of absorption of Zn (II) and Cr (III) ions into anion exchange resin and polyampholyte at different temperatures were calculated. Based on the results of the study, the thermodynamic parameters of the sorption process, the isothermal-isobaric potentials, the changes in the values of free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were found by calculating. [ABSTRACT FROM AUTHOR]

We investigated the effects of the H2S and CO gasomediators on Ca2+-dependent potassium channels and an anion exchanger, which participate in the induction of the hyperpolarization response of the erythrocyte membrane and play an important role in regulation of the volume and deformability of erythrocytes. We showed that in the presence of H2S and CO donors, the amplitude of the redox-stimulated membrane hyperpolarization decreased significantly due to a decrease in the activity of Ca2+-dependent potassium channels. It was found that H2S and CO eliminate the compression of erythrocytes observed during activation of Ca2+-dependent potassium channels or inhibition of the anion exchanger. It was shown that the H2S donor significantly increases the erythrocyte deformability. [ABSTRACT FROM AUTHOR]

Radiation hardness of vinyl-pyridinium anion exchanger of AXIONIT VPA-2 brand, synthesized at Axion–Rare and Precious Metals AO (Perm) in the process of sorption extraction of plutonium from nitrate regeneration solutions formed in waste processing and in deactivation of industrial equipment. It was found that the effects associated with the destruction of the matrix of AXIONIT VPA-2 anion exchanger become more pronounced with the absorbed dose of gamma radiation increasing within the range from 35 to 1000 kGy. A partial destruction of granules of the anion exchanger is observed, its bulk density decreases, swelling in water and nitric acid solution increases, and the plutonium distribution coefficients regularly decrease, but remain rather large. Dynamic tests demonstrated that the irradiation of AXIONIT VPA-2 anion exchanger to an absorbed gamma radiation dose not exceeding 1000 kGy has no significant effect on its sorption properties in extraction of plutonium from nitrate regeneration solutions. [ABSTRACT FROM AUTHOR]

We have studied inorganic phosphate (Pi) handling in rat aortic vascular smooth muscle cells (VSMC) using 32P-radiotracer assays. Our results have revealed a complex set of mechanisms consisting of 1) well-known PiT1/PiT2-mediated sodium-dependent Pi transport; 2) Slc20-unrelated sodium-dependent Pi transport that is sensitive to the stilbene derivatives 4,4=-diisothiocyanatostilbene-2,2=-disulphonic acid (DIDS) and 4-acetamido-4-isothiocyanostilbene-2,2-disulfonate (SITS); 3) a sodium-independent Pi uptake system that is competitively inhibited by sulfate, bicarbonate, and arsenate and is weakly inhibited by DIDS, SITS, and phosphonoformate; and 4) an exit pathway from the cell that is partially chloride dependent and unrelated to the known anion-exchangers expressed in VSMC. The inhibitions of sodiumindependent Pi transport by sulfate and of sodium-dependent transport by SITS were studied in greater detail. The maximal inhibition by sulfate was similar to that of Pi itself, with a very high inhibition constant (212 mM). SITS only partially inhibited sodium-dependent Pi transport, but the Ki was very low (14 M). Nevertheless, SITS and DIDS did not inhibit Pi transport in Xenopus laevis oocytes expressing PiT1 or PiT2. Both the sodium-dependent and sodium-independent transport systems were highly dependent on VSMC confluence and on the differentiation state, but they were not modified by incubating VSMC for 7 days with 2 mM Pi under nonprecipitating conditions. This work not only shows that the Pi handling by cells is highly complex but also that the transport systems are shared with other ions such as bicarbonate or sulfate. NEW & NOTEWORTHY In addition to the inorganic phosphate (Pi) transporters PiT1 and PiT2, rat vascular smooth muscle cells show a sodium-dependent Pi transport system that is inhibited by DIDS and SITS. A sodium-independent Pi uptake system of high affinity is also expressed, which is inhibited by sulfate, bicarbonate, and arsenate. The exit of excess Pi is through an exchange with extracellular chloride. Whereas the metabolic effects of the inhibitors, if any, cannot be discarded, kinetic analysis during initial velocity suggests competitive inhibition. [ABSTRACT FROM AUTHOR]

An anion exchange solid-phase sorbent is described. Chitosan coated magnetite nanoparticles were modified with polyethylenimine which is positively charged at pH 3 and therefore can be used for the magnet-supported enrichment of phosphopeptides which are negatively charged at this pH value. A 2-step strategy was used to synthesize the sorbent. The materials were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry and magnetic moment analysis. The anion exchanger was applied to extract phosphopeptides from a β-casein digest. Characteristic analytical figures include (a) a loading buffer of pH 3, (b) and elution buffer of pH 11, (c) a loading time of 5 min, (d) good selectivity (the β-casein to BSA ratio is 1:1000), and (e) excellent sensitivity (1 fmol). The optimized method was applied to egg yolk digest, non-fat milk digest, and diluted human serum. [ABSTRACT FROM AUTHOR]

Pendrin (SLC26A4) is an anion exchanger from the SLC26 transporter family which is mutated in human patients affected by Pendred syndrome, an autosomal recessive disease characterized by sensoneurinal deafness and hypothyroidism. Pendrin is also expressed in the kidney where it mediates the exchange of internal HCO3− for external Cl− at the apical surface of renal type B and non-A non-B-intercalated cells. Studies using pendrin knockout mice have first revealed that pendrin is essential for renal base excretion. However, subsequent studies have demonstrated that pendrin also controls chloride absorption by the distal nephron and that this mechanism is critical for renal NaCl balance. Furthermore, pendrin has been shown to control vascular volume and ultimately blood pressure. This review summarizes the current knowledge about how pendrin is linking renal acid-base regulation to blood pressure control. [ABSTRACT FROM AUTHOR]

Specific features of the interaction of granulated polyvinyl chloride with polyethylenepolyamine were examined. It was shown that, to perform the reaction, it is necessary to make the granules porous by removing from the plastic compound the plasticizer and other additives introduced into the plastic compound when granules are formed. It was found that the reaction is to be performed in two stages: to treat the plastic compound with polyethylenepolyamine, with the subsequent ripening of the product at temperatures of 423 K and above. The modification yielded an anion exchanger with properties that compare well with AH-31 industrial anion exchanger. Tests performed at MAXAM-CHIRCHIQ JSC made it possible to recommend the anion exchanger synthesized in the study for use in industrial water treatment. [ABSTRACT FROM AUTHOR]

• A novel anion exchanger by coupling rtDMC with the pendant double bonds of DVB. • An improved hydrophilic surface obtained by a simple hydrolysis treatment. • The column exhibit good chromatographic performance towards anions. An anion exchanger has been described by grafting dimethylaminoethyl methacrylate methylchloride (DMC) onto the poly(glycidyl methacrylate-divinylbenzene) (GMA-DVB) subtract. The grafting was performed by coupling of DMC with the pendant double bonds of DVB. Prior to grafting, a hydrolysis treatment to free epoxide groups associated with GMA-DVB substrate enables an improved hydrophilic surface of the obtained anion exchanger. The capacity of the obtained anion exchanger can be manipulated by controlling DMC amount to a great degree. Common seven inorganic anions onto the anion exchanger could be well separated within 20 min and high separation efficiency was obtained, e.g. 46,500/m of the plate count for chloride. [ABSTRACT FROM AUTHOR]

Abstract A novel hydrophilic polymer-based anion exchanger has been described for ion chromatography (IC). It is prepared by grafting polyethyleneimine (PEI) onto the poly(glycidylmethacrylate-divinylbenzene) (GMA-DVB) substrate, followed by hydrolytic treatment to convert the residual epoxide groups onto the surface of GMA-DVB substrates to hydroxyl groups, finally quaternized PEI by a molecule containing epoxide group. Hydrophobic surface of GMA-DVB substrate can be converted to hydrophilic, aiming to reduce unwanted non-ionic interaction from the substrate. After optimizing the reaction conditions, the obtained anion exchanger showed good separation towards standard inorganic anions under the suppressed mode and complete elution of seven common inorganic anions could be achieved in less than 16 min by using potassium bicarbonate eluent. It also demonstrated fast dynamic kinetic and enabled the separation of 7 anions within 3 min at the isocratic mode. Column efficiency of the anion exchanger was up to 34,000 /m. Graphical abstract A novel hydrophilic polymer-based anion exchanger is described for IC by grafting quaternized PEI onto GMA-DVB substrates. A hydrolytic treatment can convert hydrophobic surface into hydrophilic. fx1 Highlights • A facile way to prepare hydrophilic anion exchanger. • The column exhibit good chromatographic performance towards anions. • Very fast separation can be achieved by such column (<3 min). [ABSTRACT FROM AUTHOR]

Abstract Measuring the impedance of heated suspensions of erythrocytes and erythrocyte ghost membranes, two thermally-induced alterations are registered in the plasma membrane at T A (denaturation of spectrin with inducing temperature at 49,5 °C) and T G (hyperthermic activation of basal ion permeability with inducing temperature at 60.7 °C). In this study erythrocytes from 9 healthy patients and 15 patients with hemolytic anemia were studied and divided into four groups depending on their T A and T G top temperatures. The T A and T G of erythrocytes with hemoglobinopathy were the same as those of control erythrocytes while those of erythrocytes with membranopathy were significantly reduced. In erythrocytes with severe membranopathy, the T G was decreased by about 5 °C. In latter cells the normal value of T G was restored and the resistance to thermal haemolysis was increased by 90% after the specific stabilization of band 3 protein by 4,4′-diisothiocyanato-stilbene-2,2′-disulfonic acid (DIDS). Obtained results indicate the involvement of band 3 in the membrane alteration at T G and in the heat target responsible for thermal haemolysis. Highlights • Erythrocytes with membranopathy were studied with thermal derivative conductometry. • The denaturation temperatures of spectrin, T A , and band 3, T G , were registered. • These temperatures were reduced (T A up to 3 and T G up to 5 °C) compared to control. • The anemic cells were treated by DIDS, specific inhibitor of band 3. • DIDS restore T G value and increase the resistance to thermal haemolysis up to 90%. [ABSTRACT FROM AUTHOR]

Abstract Chemical constitution and construction of functional sites play a crucial part in the chromatographic behavior of stationary phases. We present novel polymeric anion exchangers covalently grafted with linear quaternary ammonium polyelectrolytes via simple one-step epoxy-amine polymerization. In separation of various anionic analytes, the newly developed anion exchangers showed high efficiency (e.g., >30,000 plates m−1 for chloride with hydroxide elution) and peculiar chromatographic behavior as compared to previously reported hyperbranched phases. By adopting different amines as the building unite of linear polyelectrolytes, the two types of model anion exchangers displayed segregated selectivity which in our opinion is associated with charge density, hydrophilicity and low cross-linking of the functionalities. Graphical abstract fx1 Highlights • Anion exchangers covalently grafted with linear polyquaternary ammoniums were prepared. • Chain length and swelling behavior of grafted polyelectrolytes were investigated. • A variety of anionic species was separated with high performance. • Using different amines as the building unit resulted in segregated selectivity. [ABSTRACT FROM AUTHOR]

The review covers the research of the Laboratory of Chromatography of the Division of Analytical Chemistry of the Department of Chemistry of Moscow State University in the development of new stationary phases for hydrophilic interaction liquid chromatography and ion chromatography performed in 2007–2017. The principles that guided the team in selecting matrices for each type of adsorbents, approaches to the modification of surface, and the methods of forming functional layers are discussed. The revealed regularities of changes in the chromatographic properties of materials on varying the structural fragments of the functional layers are described in detail, which enabled the authors to develop approaches to obtaining stationary phases that are not inferior to commercial analogs in efficiency and selectivity. [ABSTRACT FROM AUTHOR]

Chloride/formate exchanger (CFEX; SLC26A6) mediates oxalate transport in various mammalian organs. Studies in Cfex knockout mice indicated its possible role in development of male-dominant hyperoxaluria and oxalate urolithiasis. Rats provide an important model for studying this pathophysiological condition, but data on Cfex (rCfex) localisation and regulation in their organs are limited. Here we applied the RT-PCR and immunochemical methods to investigate rCfex mRNA and protein expression and regulation by sex hormones in the pancreas, small intestine, liver, and kidneys from intact prepubertal and adult as well as gonadectomised adult rats treated with sex hormones. rCfex cDNA-transfected HEK293 cells were used to confirm the specificity of the commercial anti-CFEX antibody. Various biochemical parameters were measured in 24-h urine collected in metabolic cages. rCfex mRNA and related protein expression varied in all tested organs. Sex-independent expression of the rCfex protein was detected in pancreatic intercalated ducts (apical domain), small intestinal enterocytes (brush-border membrane; duodenum > jejunum > ileum), and hepatocytes (canalicular membrane). In kidneys, the rCfex protein was immunolocalised to the proximal tubule brush-border with segment-specific pattern (S1=S2

Intensive development of many industries, including textile, paper or plastic, which consume large amounts of water and generate huge amounts of wastewater-containing toxic dyes, contribute to pollution of the aquatic environment. Among many known methods of wastewater treatment, adsorption techniques are considered the most effective. In the present study, the weakly basic anion exchangers such as Amberlyst A21, Amberlyst A23 and Amberlyst A24 of the polystyrene, phenol-formaldehyde and polyacrylic matrices were used for C.I. Direct Yellow 50 removal from aqueous solutions. The equilibrium adsorption data were well fitted to the Langmuir adsorption isotherm. Kinetic studies were described by the pseudo-second order model. The pseudo-second order rate constants were in the range of 0.0609–0.0128 g/mg·min for Amberlyst A24, 0.0038–0.0015 g/mg·min for Amberlyst A21 and 1.1945–0.0032 g/mg·min for Amberlyst A23, and decreased with the increasing initial concentration of dye from 100–500 mg/L, respectively. There were observed auxiliaries (Na2CO3, Na2SO4, anionic and non-ionic surfactants) impact on the dye uptake. The polyacrylic resin Amberlyst A24 can be promising sorbent for C.I. Direct Yellow 50 removal as it is able to uptake 666.5 mg/g of the dye compared to the phenol-formaldehyde Amberlyst A23 which has a 284.3 mg/g capacity.

Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica (PSi), was cross-linked with either N,N,N’,N’-tetramethyl-1,2-ethylenediamine (TEMED) or N,N,N’,N’-tetramethyl-1,3-propanediamine, followed by the reaction of the free -CH2Cl groups with N,N-diethyl-2-hydroxyethylamine to generate strong base anion exchangers (ANEX) inside the pores. The PSi/ANEX composite sorbents were deeply characterized by FTIR spectroscopy, SEM-energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water uptake. The sorption performances of composites against Cr(VI) were investigated as a function of pH, contact time, initial concentration of Cr(VI), and temperature. It was found that the cross-linker structure and the silica morphology are the key factors controlling the sorption capacity. The adsorption process was spontaneous and endothermic and well described by pseudo-second-order kinetic and Sips isotherm models. The maximum sorption capacity of 311.2 mg Cr(VI)/g sorbent was found for the composite prepared with mesoporous silica using TEMED as cross-linker. The PSi/ANEX composite sorbents represent an excellent alternative for the removal of Cr(VI) oxyanions, being endowed with fast kinetics, equilibrium in about 60 min, and a high level of reusability in successive sorption/desorption cycles.

Linear acetals have been synthesized by decomposition trans- and cis-1,1-dichloro-2,3-diphenylcyclopropanes in the presence of aliphatic alcohols (ethanol and butan-1-ol). The reactivities of pure trans- and cis-stilbenes and styrene toward dichlorocarbene have been compared. The structure of the isolated compounds was determined by NMR and GC/MS. [ABSTRACT FROM AUTHOR]

Background: Some respiratory diseases may induce alveolar hypoxia thereby hypoxic pulmonary vasoconstriction (HPV). However, the mechanisms of this physiologic phenomenon are not fully understood. This study was the first to investigate the role of anion exchanger in sustained HPV. Methods: Experiments were performed in the isolated perfused rabbit lung. After preparation, the lungs were divided into six groups: two DIDS (4,4-diisothiocyanostilbene 2,2-disulfonic acid, anion exchanger inhibitor)-treated [200 µM (n=5) or 400 µM (n=3)] hypoxic groups, two HCO3- free hypoxic groups, one control hypoxic group (n=7) and one control normoxic group (n=4). DIDS were added to the perfusate at 10 minutes before starting the experiments. In the HCO3- free groups, HEPES (4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid) were added to the perfusate instead of bicarbonate. Furthermore, in the HEPES1 (n=4) and HEPES2 (n=4) groups, the lungs were ventilated with hypoxic gas with or without CO2, respectively. Results: Ventilation of the lungs with hypoxic gas resulted in biphasic HPV, the acute (0-20 minutes) and sustained (20-60 minutes) phases. No alteration in both phases of HPV was detected by DIDS (200 µM). However, DIDS (400 µM), extended the ascending part of acute HPV until min 24. Both phases of HPV were decreased in the HEPES1 group. However, in the HEPES 2 group, HPV tended to increase during the rising part of the acute phase of HPV. Conclusions: Since DIDS (400 µM) extended acute phase of HPV, and HCO3- free perfusate buffer enhanced rising phase of it, therefore it can be suggested that anion exchanger may modulate HPV especially during the acute phase. The abstract of this article was presented as a poster in the congress of European Respiratory Society (ERS) on Monday, 08 September 2014, Munich, Germany and was published in the ERJ September 1, 2014 vol. 44 no. Suppl 58 P2343.

Phenomenon of rising sorption capacity of AV-17-8 anion exchanger upon an increase in its humidity due to the superequivalent absorption of Cl- ions was revealed and substantiated. The purification of halogensubstituted hydrocarbon solvents to remove acids under dynamic conditions by the ion-exchange method and the dynamics of sorption by anion exchangers of halogen-substituted solvents from model solutions were studied. It was shown that AV-17-8 anion exchanger is stable in halogen-substituted solvents and, when present in the OH-form, raises their stability against destruction, and the equilibrium sorption capacity of the anion exchanger is 2-3 times its exchange capacity. [ABSTRACT FROM AUTHOR]

World widely, the excess loads of phosphorus (P) is one of the most common chemical contamination in freshwater bodies (e.g. lakes and rivers), which is one of the major causes of eutrophication. Effluents from wastewater treatment plant (WWTP) are considered to contribute up to 60%–80% of the P in rivers due to discharge of treated effluents often containing residual P concentrations of 1–2 mg/L. In this study, Ca and Mg incorporated layered double hydroxide (LDH) adsorbents were synthesized and assessed for phosphate removal from both P spiked synthetic solution and real effluent sample of a WWTP to provide a comparative overview of using such LDHs as a P removal treatment option in WWTPs. The phosphate removal with Ca-type LDHs were 85%–99%, whereas the removal with Mg-type LDHs were <50% under the same operating conditions, suggesting a significant influence of the type of precursor metals in synthesizing LDH compounds for removing phosphate. However, the Mg-type LDH up to 2 g/L can provide a similar P removal as Ca-type LDHs at the dose of 0.3 g/L to reduce P concentration to 0.1 mg/L from an initial concentration of 10 mg/L. The effluent from WWTP’s secondary treatment process with P concentration of 1.4‒5.6 mg/L can be treated by both types of LDH to meet future stringent discharge limit at the concentration of 0.1 mg/L. The Mg-type LDH showed mineral stability and regeneration efficiency with ligand exchange and anion exchange as the main mechanism for P removal, while the Ca-type LDH removed P as calcium–phosphate precipitation due to dissolution with broken layered structure in aqueous phase. Overall, both of Ca- and Mg-type LDHs can be potentially applied for tertiary treatment step with the WWTP’s conventional treatment process to further polishing P discharge level. But future studies are required to investigate the effect of practical wastewater conditions (medium-term) and estimate costs of application (long-term) of using LDHs for phosphorous removal in real wastewater treatment. [ABSTRACT FROM AUTHOR]