Concentrations Of Chloride Anions Research Articles

Chloride Adsorption on Au (111) Electrodes

There are still numerous open questions with regards to adsorption phenomena and partial charge transfer at electrode interfaces. The dynamic nature electrode structure and adsorbate ordering makes an analysis solely based on thermodynamic considerations limited. Here we present recently collected data with such an analysis, using different concentrations of chloride anions in both acidic and neutral electrolytes, for well-defined Au (111) electrodes. Cyclic voltammograms and charge density data is obtained. Then the electrocapillary equation: "-dγ = σMdE + ΓCl-RTdln(cKCl)" is used to get the relative interfacial tension plot and later the electrosorption valency. In the future we will improve on this by more accurately placing the PZC of charge density measurements, using laser induced temperature jump transients and combining our interpretation with state-of-the-art molecular-dynamics using ground state machine learned potentials. Figure 1

The suppressive effect of the specific KCC2 modulator CLP290 on seizure in mice

Epilepsy is a chronic neurological disorder characterized by episodic dysfunction of central nervous system. The most basic mechanism of epilepsy falls to the imbalance between excitation and inhibition. In adults, GABAA receptor (GABAAR) is the main inhibitory receptor to prevent neurons from developing hyperexcitability, while its inhibition relies on the low intracellular chloride anion concentration ([Cl-]i). Neuronal-specific electroneutral K+-Cl− cotransporter (KCC2) can mediate chloride efflux to lower [Cl-]i for GABAAR mediated inhibition. Our previous study has revealed that the coordinated downregulation of KCC2 and GABAAR participates in epilepsy. According to a high-throughout screen for compounds that reduce [Cl−]i, CLP290 turns out to be a specific KCC2 functional modulator. In current study, we first confirmed that CLP290 could dose-dependently suppress convulsant-induced seizures in mice in vivo as well as the epileptiform burst activities in cultured hippocampal neurons in vitro. Then, we discovered that CLP290 functioned through preventing the downregulation of the KCC2 phosphorylation at Ser940 and hence the KCC2 membrane expression during convulsant stimulation, and consequently restored the GABA inhibition. In addition, while CLP290 was given in early epileptogenesis period, it also effectively decreased the spontaneous recurrent seizures. Generally, our current results demonstrated that CLP290, as a specific KCC2 modulator by enhancing KCC2 function, not only inhibits the occurrence of the ictal seizures, but also suppresses the epileptogenic process. Therefore, we believe KCC2 may be a suitable target for future anti-epileptic drug development.

On‐line chloride removal from ion chromatography for trace‐level analyses of phosphite and other anions by coupled ion chromatography–inductively coupled plasma mass spectrometry

RationaleIon chromatography (IC) combined with inductively coupled plasma mass spectrometry (ICPMS) is an ideal tool for measuring low concentrations of anionic species such as phosphite; however, the high concentration of chloride and other anions in natural solutions may negatively impact chromatographic separation and data quality.MethodWe developed an on‐line mechanism of removing chloride from a sample within an ion chromatograph, using an additional valve and a separation column that transfers chloride to waste while phosphite and most other anions are retained. We installed this system in a coupled IC/ICPMS system (ICS6000 and Element 2 in medium‐resolution mode) and determined linearity and detection limits. In addition, we measured phosphorus species by NMR for comparison as an alternative method for phosphite determination.ResultsChloride was fully removed from the samples while phosphite was retained and could be analysed by IC/ICPMS. Concentrations could be measured down to 0.003 μmol/L and possibly less with good linearity over the explored range (up to 1.615 μmol/L; r2 = 0.999). In contrast, the detection limit by NMR was 6.46 μmol/L.ConclusionsThe on‐line removal mechanism works well for simplifying sample matrices. It removes the need for costly pre‐analytical sample treatment with OnGuard columns. We confirm that IC/ICPMS is the most powerful technique for quantifying phosphite in natural solutions. The new chloride‐removal method may also be applicable to analyses of other anions.

O2 Affinities of Hemoglobin Variants Having a Different Amino Acid at the Position α99

We prepared six recombinant hemoglobin A variants [rHb(X)], in which Lys-α99 residues are replaced with different amino acids. The mutations with neutral amino acids decreased the O2 affinity and increased the dissociation constant of the Hb tetramer (α2β2) to two αβ dimers. In particular, rHb(Lys-α99→Ala) showed the moderately low O2 affinity, which was insensitive to chloride anion concentration. The Ala mutant could be a promising material for artificial O2 carrier as red blood cell substitute.

Synthesis of a Golgi-targeting fluorescent probe for the selective detection of chloride anions.

In this paper, we describe the synthesis and properties of a Golgi-targeting fluorescent probe for the selective detection of chloride anions. Specifically, we have synthesized one quaternized quinoline derivative bearing a sulfanilamido group and found that this compound is able to primarily target the Golgi apparatus and detect the changes in the concentration of cellular chloride anions.

Hydrology of a hydroperiod: Assessing recharge to the High Plains aquifer through a playa in western Kansas

Playa lakes have been promoted as potential point sources of recharge to the High Plains aquifer, but information about recharge rates is only available for the Southern High Plains, where soils and substrate differ significantly from the Central High Plains. The goal of this study is to determine the degree to which functioning playas contribute to recharge of the aquifer in the Central High Plains. This is accomplished through a multifaceted study across a single 34–43 day-long playa hydroperiod, combining physical and geochemical evidence to measure fluid flux through the playa and geochemical evidence of fluid flux through the nearby interplaya. The hydroperiod resulted in increased matric potential and decreases in chloride and other anion concentrations in the vadose zone beneath the playa, and increases in groundwater levels downgradient, likely indicating recharge to the aquifer over the course of the short event. Anion concentrations are significantly higher in the interplaya compared with the playa, while fluid flux estimates are significantly higher beneath the playa. The fluid fluxes determined in this study are consistent with estimates from elsewhere in the High Plains region. The combination of physical and geochemical data decreased the uncertainty and improved the overall conclusion that recharge rates are higher beneath the playa than the interplaya, providing evidence that playas in the Central High Plains function similarly to those in the Southern High Plains.

On the frequency response of prestin charge movement in membrane patches

Outer hair cell (OHC) nonlinear membrane capacitance derives from voltage-dependent sensor charge movements within the membrane protein prestin (SLC26a5) that drive OHC electromotility. The ability of the protein to influence hearing depends on its reaction to membrane receptor potentials across auditory frequency. Estimates of prestin’s frequency response have been evaluated by several groups out to tens of kHz in voltage-clamped macro-patches of OHC membrane. The response is a power function of frequency that is down 40 dB at 77 kHz. Despite these observations, concerns remain that the macro-patch approach is flawed due to mechanical constraints of pipette solution column load or patch size itself. In the absence of these influences, prestin’s frequency response is posited by some to be ultrasonic in nature. Here we evaluate the influence of these putative confounding factors on prestin’s frequency response. We show that neither pipette column height nor negative or positive pipette pressure substantially influence total sensor charge frequency response. Additionally, patch surface area has negligible influence. We conclude that the speed of voltage-driven conformational changes in prestin within the plasma membrane is accurately assessed with the macro-patch technique, permitting investigations of membrane characteristics that can substantially alter prestin’s performance bandwidth. We illustrate significant alterations in bandwidth by perturbation of membrane fluidity and chloride anion concentration. Finally, we speculate that OHC membrane characteristics may differ along the tonotopic axis of the cochlea to tune nonlinear membrane capacitance frequency cutoffs.

Furosemide prevents membrane KCC2 downregulation during convulsant stimulation in the hippocampus.

In adults, γ-aminobutyric acid (GABA) type A receptor (GABAAR)-mediated inhibition depends on the maintenance of low intracellular chloride anion concentration through neuron-specific potassium-chloride cotransporter-2 (KCC2). KCC2 has been widely reported to have a plasticity change during the course of epilepsy development, with an early downregulation and late recovery in neuronal cell membranes after epileptic stimulation, which facilitates epileptiform burst activity. Furosemide is a clinical loop diuretic that inhibits KCC2. Here, we first confirmed that furosemide pretreatment could effectively prevented convulsant stimulation-induced neuronal membrane KCC2 downregulation in the hippocampus in both in vivo and in vitro cyclothiazide-induced seizure model. Second, we verified that furosemide pretreatment rescued KCC2 function deficits, as indicated by EGABA depolarizing shift and GABAAR inhibitory function impairment induced via cyclothiazide treatment. Further, we demonstrated that furosemide also suppressed cyclothiazide-induced epileptiform burst activity in cultured hippocampal neurons and lowered the mortality rate during acute seizure induction. Overall, furosemide prevents membrane KCC2 downregulation during acute seizure induction, restores KCC2-mediated GABA inhibition, and interrupts the progression from acute seizure to epileptogenesis.

STUDY OF SOME PHYSICAL AND CHEMICAL PROPERTIES OF WATER THAT GOES IN, THEN OUT OF THE DESALINATION PLANT AT AL-KHUMS CITY

The analysis of entering water samples, gave an average value for pH (7.98), but yielded water samples show a slight change in the pH (8.06), while the value of conductivity EC for sea water was (53501µs/cm), then, significant decrease has been recorded in yielded water samples to become (32.032µs/cm). The chemical analysis also showed a major difference in the measurement for both of total dissolved salts TDS, and salts causing hardness TH, between entering and yielded water samples, as same as for sodium and potassium, where the average value of their concentrations in water samples that goes inthe desalination plant were (10380ppm)&(444ppm), to become (5.358ppm)&(0.24ppm)in water that goes outof desalination plant, respectively. A big difference was also observed in the average concentration of chloride and sulfate anions, in which the amount of chlorine was (19644ppm)and for sulfate (2752ppm)insea water, however at yielded water bothof them were (2.292ppm)and (1.389ppm)respectively.

Biochemical and hematological parameters of the roach Rutilus rutilus heckelii (Nordmann, 1840) from the Sea of Azov stock in the spring season of 2020–2021

This work presents the results of the investigation of the physiological state of the roach Rutilus rutilus heckelii breeders from the Sea of Azov stock during the spawning period. It has been established that, in the spring season of 2020 and 2021, the content of proteins and lipids in fish tissues, as well as hematological parameters in all investigated roach specimens from different water bodies were consistent with the average long-term values. The content of proteins in the muscles and liver of roach does not differ by sex. A higher protein content in the gonads of females is characteristic of the pre-spawning period due to the process of gonad maturation. The high content of lipids in the gonads of males apparently results from the lower energy consumption for maturation of the gonads and spawning. The average concentration of sodium and potassium ions decreased in comparison with the values obtained in 2020, while the concentration of chloride anions increased. It has been concluded that the physiological state of all investigated roach specimens was normal.

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Geochemical modeling of mercury in coastal groundwater

The systematic analysis of groundwater in the Greek island of Skiathos revealed a seasonal increase of total mercury concentrations after the extensive groundwater abstraction during the busy and heavily touristic summer months. This contamination was accompanied by a corresponding increase of the chloride content of groundwater, attributed to seawater intrusion into the freshwater-depleted aquifer within mercury-rich bedrock. The effects of elevated concentrations of chloride anions in the mobilization of mercury and its speciation were addressed by geochemical equilibrium modeling, considering cinnabar (HgS) as the mineral source of mercury. Adsorption onto hydrous ferric oxide (Fe2O3·H2O) was a necessary ingredient of the geochemical model for bringing the calculated concentrations in agreement with field measurements, after optimization of the cinnabar/adsorbent mass ratio to a value of 4.9 × 10−8. The speciation of mercury was found to depend on the acidity and redox status as well as on the chloride content of groundwater. Mercury concentrations in the groundwater of Skiathos rise above the World Health Organization limit of 1 μg L−1 for a seawater intrusion higher than 3 %, with HgCl2 being the dominant species followed by HgClOH, HgCl3− and HgCl42−. The assumed concentration of dissolved organic matter in groundwater had a negligible impact on the mercury speciation and its mobilization by chloride.

A bespoke chloride sensor for seawater: Simple and fast with a silver electrode

Chloride quantification in natural seawater is important in both oceanography and corrosion science. A bespoke electrochemical method was developed for a facile and accurate chloride sensor specifically for use for the high chloride levels encountered in seawater (ca 0.5 M). This is based on the voltammetric oxidation of a silver electrode over a well-defined potential range corresponding to AgCl nucleation/formation. The peak current for silver chloride formation varies linearly with chloride concentration in the range 0.484 M–0.624 M provided the electrode is suitably activated. In particular, the reduction of dissolved oxygen was found to clean the surface and also to provide a stable peak potential against which other potentials can be referenced if it is wished to use a quasi-reference electrode. Thus, the overall voltammetric scan embraces first the reduction of oxygen followed by silver chloride formation and stripping. Reliable quantification was achieved in synthetic seawater with this methodology. Furthermore, the chloride anion concentration in three different authentic samples of natural seawater was measured accurately giving excellent agreement with independent analysis.

Snow mass characteristics for the indication of the ice-melting products application load

Introduction. For the time present, the active substances of many ice-melting agents used in Moscow are technical sodium and calcium chlorides. By degree of impact of sodium chloride on the human body is characterized as a moderately dangerous substance that belongs to the 3rd hazard class. Residents of megacities who remain unprotected from the possible harmful effects of these substances need the compliance of the ice-melting product’s application with appropriate security measures. Our research focused on the presence of these substances and their accompanying components in the transit environment and determining their actual and extreme loads to prevent possible functional changes in the future traffic chain objects. Material and methods. Chloride (Cl-) and sodium (Na+) content in the snow mass samples taken from the sites adjacent to motorways in Moscow were determined using ion chromatography. Other associated elements in the ice-melting agents were detected using inductively coupled plasma mass spectrometry method (ICP-MS). Results. According to the snow mass analysis as an object of transit accumulation and distribution of ice-melting reagents, the authors ranked results and identified clusters with different degrees of contamination for many indices. Selecting the group with very high contamination enabled us determine the indices’ levels that limit the use of deicing reagents. When using sodium-chloride reagents, they are the levels of the specific electrical conductivity (SEC) ≥ 4500 µS/cm, the concentration of chloride anions (Cl- ≥ 2500 mg/l), the concentration of sodium ions (Na+) ≥1500 mg/l, the index of total contamination (Zc).

Facilitated Transport of Copper(II) across Polymer Inclusion Membrane with Triazole Derivatives as Carrier.

This study investigates copper(II) ion transport through a polymer inclusion membrane (PIM) containing 1-alkyl-1,2,4-triazole (n = 8, 9, 10, 11, 12, 14), o-nitrophenyl octyl ether as the plasticizer and cellulose triacetate as the polymer matrix. The feeding phase was a solution of 0.1 mol/dm3 CuCl2 and an equimolar (0.1 mol/dm3) mixture of copper, nickel, and cobalt chlorides with varying concentrations of chloride anions (from 0.5 to 5.0 mol/dm3) established with NaCl. The receiving phase was demineralized water. The flow rate of the source and receiving phases through the membrane module was within the range from 0.5 cm3/min to 4.5 cm3/min. The tests were carried out at temperatures of 20, 30, 40 and 50 °C. Transport of NaCl through the membrane was excluded for the duration of the test. It was noted that the flow rate through the membrane changes depending on the length of the carbon chain in the alkyl substituent from 16.1 μmol/(m2s) to 1.59 μmol/(m2s) in the following order: C8 > C9 > C10 > C11 > C12 > C14. The activation energy was 71.3 ± 3.0 kJ/mol, indicating ion transport through the PIM controlled with a chemical reaction. Results for transport in case of the concurrent separation of copper(II), nickel(II), and cobalt(II) indicate a possibility to separate them in a selective manner.

Optical and Morphological Properties of Single-Phased and Dual-Emissive InP/ZnS Quantum Dots via Transition Metallic and Inorganic Ions.

Single-phased and dual-emissive nanocrystals with broad emission are attractive fluorescent materials for optoelectronic devices due to their unique properties. Until now, the effect of different metallic cations and inorganic anions on III-V group quantum dots (QDs) concerning luminescence features and crystalline growth has been less explored. In this work, dual-emissive InP/ZnS QDs single-doped with transition-metal compounds (Cu2+, Ag+, or Mn2+) are synthesized to compare their optical and morphological properties. The corresponding doping concentrations to realize dual emission with comparative intensity for Cu, Ag, and Mn are 0.8, 6, and 80%, which vary greatly and might be attributed to different precursor reactivities. As for the morphological and internal structures, transmission electron microscopy (TEM) images indicate that transition-metal ions have no obvious effect on the morphological properties and a higher concentration of chloride anions binding with an In-rich interface could conduce to a homogeneous distribution and triangular growth through the comparison of different metal chlorides as precursors. X-ray photoelectron spectroscopy (XPS) results further demonstrate that the high-resolution In 3d spectrum of Mn-doped InP/ZnS QDs with MnCl2 is mainly dominated by In-P bonds, indicating fewer intermediate chemical states. These results concerning well-defined InP/ZnS QDs could promote more diverse insight into surface chemistry and help to better understand the growth mechanism, thus making it possible to regulate InP/ZnS QDs into desired formats for different practical applications like white light-emitting diodes (LEDs).

Importance of Tyr409 and Tyr414 in constructing the substrate pocket of human aminopeptidase B.

Aminopeptidase B (APB, EC 3.4.11.6) preferentially hydrolyzes basic amino acids of synthetic substrates and requires a physiological concentration of chloride anions for optimal activity. Several amino acid residues of APB responsible for its enzymatic activity have been elucidated. In this study, we further searched for residues critical to its enzymatic activity, especially toward peptide substrates. APB residues Tyr409 (Y409) and Tyr414 (Y414), both of which were critical to its hydrolytic activity toward synthetic substrates, were predicted by molecular modeling to be involved in cleaving peptide substrates via its interaction with amino acids in the P1' cleavage site. Using site-directed mutagenesis, several mutant APBs were prepared. In contrast to synthetic substrates, wild-type and Y409F/Y414F double mutant enzymes showed P1'-dependent cleavage of peptide substrates, indicating that both tyrosine residues were not indispensable for hydrolytic activity toward peptide substrates. Moreover, the Y409F/Y414F double mutant enzyme cleaved peptides with a Pro residue at the P1' site, which is uncommon among the M1 family of aminopeptidases. These results suggested that Tyr409 and Tyr414 of APB play important roles in enzymatic function and characteristic properties of APB via proper formation of the S1' site.

PROPERTIES OF THE FILTRATE FORMED AFTER TERMINATION OF THE OPERATION OF THE LANDFILL

The hazardous factors influencing the disposal of solid household waste on the components of the environment belongs to the filtrate, the formation of which does not stop after the cessation of the operation of landfills. To solve the problem of environmental hazard of the filtrate can be done through the implementation of phased environmental measures. Priority measures include the arrangement of a system for collecting and removing filtrate from the landfill body. The main environmental measures are to clean the removed filtrate. The research of the properties of the filtrate of each individual landfill is necessary to justify the choice of the most effective methods of cleaning it. The purpose of the work was to study the properties of the filtrate, which continues to be formed after the cessation of the operation of the landfill of municipal solid waste in the city of Lviv. It is established that the studied filtrate is a solution with a high concentration of chemical compounds. For most indicators of filtrate is characterized by seasonal dynamics. After the warm season, the COD and BOD5 in the filtrate is increases the concentration of chloride anions, ammonium nitrogen, total iron increases; decreases the content of nitrates, nitrites and petroleum products. The indicators of filtrate, which do not change during the seasons, include the content of sulphates, phosphates and heavy metals (copper, lead, zinc). The filtrate, which continues to be formed at the municipal solid waste landfill, tends to reduce the content of heavy metals (copper, zinc, lead), ammonium nitrogen, chlorides and COD and an increase in the content of anions (phosphates, sulfates, nitrites, nitrates), oil products and BOD5. The studied filtrate does not meet the requirements for the composition and properties of wastewater discharged in-to the central city system for the content of chlorides, sulfates, nitrates, nitrites, ammonium nitrogen, lead, zinc, total iron. The filtrate can be discharged into the wastewater system only after pretreatment using methods that ensure that the filtrate indicators comply with the permissible values of indicators in the wastewater sample, the established re-quirements for the composition and properties of wastewater discharged into the wastewater system.

Effect of Increasing Concentrations of Chloride, Nitrate and Sulphate Anions with Their Counter Cations of Potassium, Sodium and Ammonium on Sulphur Bio-Oxidation by Sulphur Oxidizing Microorganisms

Effect of Increasing Concentrations of Chloride, Nitrate and Sulphate Anions with Their Counter Cations of Potassium, Sodium and Ammonium on Sulphur Bio-Oxidation by Sulphur Oxidizing Microorganisms

The Effect of Chloride Anions on Charge Transfer in Dye-Sensitized Photoanodes for Water Splitting.

The photoelectrochemical behavior of dye-sensitized photoelectrochemical cells based on a TiO2 layer sensitized with ruthenium components, including an absorber, ruthenium(II)bis(2,2′-bipyridine)([2,2′-bipyridine]-4,4′-diylbis(phosphonic acid)) dibromide (RuP), and a catalyst, ruthenium(II) tris(4-methylpyridine)(4-(4-(2,6-bis((l1-oxidanyl)carbonyl)pyridin-4-yl)phenyl) pyridine-2,6-dicarboxylic acid) (RuOEC), was investigated in the following water-based electrolyte configurations: KCl (pH ≈ 5), HCl (pH ≈ 3), ethylphoshonic acid (pH ≈ 3) with a different KCl concentration, and a standard phosphate buffer (pH ≈ 7). The rate of charge transfer on the photoanode’s surface was found to increase in line with the increase in the concentration of chloride anions (Cl−) in the low pH electrolyte. This effect is discussed in the context of pH influence, ionic strength, and specific interaction, studied by cyclic voltammetry (CV) in dark conditions and upon illumination of the photoanodes. The correlations between photocurrent decay traces and CV studies were also observed.