High Potassium Ion Concentration Research Articles

Polyelectrolyte Additive-Modulated Interfacial Microenvironment Boosting CO2 Electrolysis in Acid.

Acidic CO2 electrolysis offers a promising strategy to achieve high carbon utilization and high energy efficiency. However, challenges still remain in suppressing the competitive hydrogen evolution reaction (HER) and improving product selectivity. Although high concentrations of potassium ions (K+) can suppress HER and accelerate CO2 reduction, they still inevitably suffer from salt precipitation problems. In this study, we demonstrate that the sulfonate-based polyelectrolyte, polystyrene sulfonate (PSS), enables to reconstruct the electrode-electrolyte interface to significantly enhance the acidic CO2 electrolysis. Mechanistic studies reveal that PSS induces high local K+ concentrations through the electrostatic interaction between PSS anions and K+. In situ spectroscopy reveals that PSS reshapes the interfacial hydrogen-bond (H-bond) network, which is attributed to the H-bonds between PSS anions and hydrated proton, as well as the steric hindrance of the additive molecules. This greatly weakens proton transfer kinetics and leads to the suppression of undesirable HER. As a result, a Faradaic efficiency of 93.9 % for CO can be achieved at 250 mA cm-2, simultaneous with a high single-pass carbon efficiency of 72.2 % on commercial Ag catalysts in acid. This study highlights the important role of the electrode-electrolyte interface induced by polyelectrolyte additives in promoting electrocatalytic reactions.

Microdialysis-integrated HPLC system with dual-electrode detection using track-etched membrane electrodes for in vivo monitoring of dopamine dynamics

A capillary high-performance liquid chromatography (HPLC) system equipped with a dual-electrode detector utilizing track-etched membrane electrodes (TEMEs) was combined with a microdialysis sampling setup. The electrochemical detector benefits from the high electrolysis efficiency of TEMEs, allowing for calibration-free coulometric detection and simplifying data analysis to determine the dopamine recovery through a dialysis probe. Additionally, this system was used for in vivo monitoring of dopamine in the right striatum of a mouse brain. Temporal changes in dopamine levels, including an exponential decay immediately after the dialysis probe insertion and an excess release of dopamine induced by a high concentration of potassium ions, confirmed the system’s proper operation. Furthermore, subsequent measurements following the intraperitoneal injection of mirtazapine showed no increase in dopamine levels in the right dorsal striatum. The dual-electrode system displayed characteristic dopamine detection behavior, with anodic and cathodic peak pairs indicative of reversible electrochemical reactions. This capability facilitated the identification of the dopamine peak within the complex chromatogram of the mouse brain dialysate. The consistency between dopamine collection efficiency from standard solutions and dialysate indicated the absence of interfering electroactive substances overlapping with the dopamine peak in the chromatogram. This integrated analysis system successfully tracked temporal fluctuations in dopamine concentration within the mouse brain.

Polyelectrolyte Additive‐Modulated Interfacial Microenvironment Boosting CO2 Electrolysis in Acid

Acidic CO2 electrolysis offers a promising strategy to achieve high carbon utilization and high energy efficiency. However, challenges remain in suppressing the competitive hydrogen evolution reaction (HER) and improving product selectivity. High concentrations of potassium ions (K+) can suppress HER and accelerate CO2 reduction, but they still inevitably suffer from salt precipitation problems. In this study, we demonstrate that the sulfonate‐based polyelectrolyte, polystyrene sulfonate (PSS), enables to reconstruct the electrode‐electrolyte interface to significantly enhance the acidic CO2 electrolysis. Mechanistic studies reveal that PSS induces high local K+ concentrations through electrostatic interaction between PSS anions and K+. In situ spectroscopy reveals that PSS reshapes the interfacial hydrogen–bond (H–bond) network, which is attributed to the H–bonds between PSS anions and hydrated proton as well as the steric hindrance of the additive molecules. This greatly weakens proton transfer kinetics and leads to the suppression of undesirable HER. As a result, a Faradaic efficiency of 93.9% for CO can be achieved at 250 mA cm–2, simultaneous with a high single‐pass carbon efficiency of 72.2% on commercial Ag catalysts in acid. This study highlights the important role of the electrode‐electrolyte interface induced by polyelectrolyte additives in promoting electrocatalytic reactions.

Transformation behavior of hazardous jarosite into recyclable hematite in a solution with high concentrations of K+ and Na+

Iron in the leaching solution with high K+ and Na+ concentrations was usually precipitated as the typical hazardous and toxic jarosite residues. However, this method of treatment has been greatly restricted by increasingly strict environmental regulations. Here we propose that iron can be precipitated from the solution with high K+ and Na+ concentrations as recyclable hematite products by adjusting the concentration ratio of sodium and potassium ions in the solution. The transformation behavior of jarosite into hematite in high concentration potassium ion and sodium ion solution was explained based on collision theory. The results indicated that in instances where the concentration ratio of Na+/K+ is ≥ 4:1, the iron present in the solution can be effectively precipitated as a recyclable hematite product, as opposed to forming the conventional hazardous jarosite residue, even under conditions where the potassium ion concentration reaches levels as high as 4 g/L. On the other hand, thermodynamic and molecular dynamics simulations indicate that at a temperature of 185 °C, the decomposition transformation of Na-jarosite (32.64 kJ and 7.25 eV) is more energetically advantageous compared to that of K-jarosite (61.07 kJ and 15.31 eV). The results were verified by the leaching solution from smelting industry. The iron content in the residues is above 58%, the sulfur content is below 4%, the zinc content is below 1%, and the total iron concentration in the supernatant is about 4 g/L, reaching the production index of the smelting industry. The green, environmentally friendly, and recyclable separation of iron in a solution with high concentrations of potassium and sodium ions is achieved, which is of great significance for the treatment of iron-containing solution and wastewater in the chemical industry and metallurgy fields.

Association of hypertension in pregnancy with serum electrolyte disorders in late pregnancy among Cameroonian women

Multiple electrolyte disorders, including sodium, potassium and calcium disorders, have been associated with hypertension in pregnancy. Most of these studies failed to evaluate the combined effect of low and high sodium, potassium, calcium and chloride ion concentrations on hypertension in pregnancy. This study evaluates the combined effect of these ion categories (low, normal, high) on hypertension in pregnancy. Biochemical ion assays and blood pressure measurements were carried out on 1074 apparently healthy pregnant women in late third trimester. Serum potassium, sodium, chloride, and ionised calcium were measured by ion-selective electrode potentiometry, while total plasma calcium was measured by absorption spectrophotometry. Hypertension in pregnancy was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. The prevalence of hyponatraemia, hypokalaemia, hypochloraemia, ionised hypocalcaemia and total hypocalcaemia in late pregnancy was 1.30 [0.78–2.18]%, 3.55 [2.60–4.84]%, 1.96 [1.28–2.97]%, 1.49 [0.92–2.21]% and 43.58 [40.64–46.56]%, respectively. Hypernatraemia, hyperkalaemia, hyperchloraemia, ionised hypercalcaemia and total hypercalcaemia were found in 1.49 [0.92–2.41]%, 2.34 [1.59–3.43]%, 4.38 [3.31–5.77]%, 39.94 [37.06–42.90]%, 2.79 [1.96–3.96]% of the participants, respectively. The prevalence of hypertension in pregnancy was 7.17 [5.77–8.87]%. When ion categories were considered in multiple logistic regression, only ionised and total calcium had significant associations with hypertension in pregnancy. Women with ionised hypercalcaemia had lower odds of hypertension in pregnancy (AOR = 0.50 [0.29–0.87], p-value = 0.015), and women with total hypocalcaemia had higher odds of hypertension in pregnancy (AOR = 1.99 [1.21–3.29], p-value = 0.007), compared to women with ionised and total normocalcaemia, respectively. Increasing kalaemia was associated significantly with higher odds of hypertension in pregnancy; however, kalaemia below and above the normal concentrations had no significant association with hypertension. Nonetheless, participants with kalaemia ≤ 3.98 mmol/L, had lower odds of hypertension in pregnancy compared with those with higher kalaemia (OR = 0.40 [0.24–0.66], p-value = 0.0003). Calcium disorders remain the most frequent electrolyte disorders in pregnancy. When normal cut-offs are considered for calcium and other ions, only ionised and total calcium influence the occurrence of hypertension in pregnancy. Kalaemia seems to affect hypertension in pregnancy but primarily within its normal concentrations. Serum electrolyte follow-up is indispensable for a proper pregnancy follow-up.

Zein-enhanced sodium alginate/thiostannate microsphere adsorbent Zein@SA/KBS for efficient removal of cesium from wastewater

Although efficient removal of Cs from wastewater is of great importance because of the nuclear energy sustainable development and public health, removing cesium is challenging for the high concentrations of sodium and potassium ions coexist. In this work, we synthesized the first novel bismuth-doped layered tin sulfide (KBS) and applied it to the efficient green adsorption of liquid cesium resources. KBS could reach the adsorption equilibrium for Cs+ within only 2 min with a theoretical adsorption capacity of 425.55 mg/g. Furthermore, the adsorption performance remained reliable after 10 cycles of use. The structure and properties of KBS were explained at the molecular level by DFT calculations, and the calculated results were in sound agreement with the experimental data. Meanwhile, in this study, the material was reinforced and shaped by the electrostatic interaction of Zein and sodium alginate hydrogel, and finally, Zein@SA/KBS spherical composite adsorbent was obtained. The problem of the difficult recovery of adsorbent and the secondary contamination was solved. The adsorption performance of Zein@SA/KBS on Cs+ was better than most composite adsorbents and showed reliable stability. Therefore, the new microspherical adsorbent (Zein@SA/KBS) has great potential for industrial application in removing radioactive cesium from wastewater.

A two-step green liquid-liquid extraction strategy for selective lithium recovery and application to seawater

Efficiently harvesting lithium from seawater remains a challenge due to the extremely dilute concentration of lithium ions (Li+) and the existence of many foreign metal ions that are far more abundant. Here, a hydrophobic deep eutectic solvent (HDES)-based two-step liquid-liquid extraction (LLE) strategy is developed for the first time that realizes the separation of dilute Li+ (<1 mg/L) from solutions with a high concentration of sodium, potassium, magnesium and calcium ions. This strategy contains the removal of divalent cations and selective recovery of Li+, which minimizes the influence of coexisting metal ions. In the first LLE step, the unwanted divalent cations are removed with a negligible loss of Li+ by the bis(2-ethylhexyl)phosphate/kerosene (DEHPA/KERO) system. Then, the DEHPA/HDES system can selectively extract Li+ from monovalent cations. All solvents used are readily available and low cost with methyltrioctylammonium chloride and decanoic acid at a 1:2 mol ratio (N8881Cl/2DecA) as the main extractant. Extraction equilibrium is reached within 10 s. The single extraction efficiency of Li+ is 66.4%, and the separation coefficient of lithium and sodium (βLi/Na) reaches 11.6 at the optimized extraction conditions. Finally, the proposed two-step LLE strategy is applied to the simulated seawater. The extraction performance of N8881Cl/2DecA-DEHPA was not significantly weakened after being reused ten times.

Extraction of rubidium ion from brine solutions by dicyclohexano-18-crown-6 / ionic liquid system

Abstract Separation among rubidium and potassium ions from salt lake brines remains challenging. In this work, a typical room temperature ionic liquid 1-ethyl-3-metyhlimidazaolium bis(trifluoromethylsulfonyl)imide ([C2mim+][NTf2 –]) was used as diluent and synergistic extractant, dicyclohexano-18-crown-6 (DCH18C6) was used as extractant to extract rubidium ions from brine solutions which contain high concentrations of potassium ions was investigated. Under the optimal conditions, the single extraction efficiency of rubidium ions was up 93.63%. The thermodynamic parameters of the rubidium ion extraction were obtained. Based on the slope analysis method, the extracted species in the organic phase were ascertained as 1:1 complex. UV-visible has been performed to investigate the ion concentration of ionic liquid before and after the interaction of metal ions and ligands. Rubidium ions in [Rb · DCH18C6]+ complex were stripped by 2.5 mol · L–1 NH4NO3. The extraction system offers high efficiency, simplicity and environmentally friendly application prospect to separate rubidium from brine solutions.

Potassium from micaceous clay for the origins of life

This hypothesis for the origins of life includes recent research results in areas such as Liquid-Liquid Phase Separation by Brangwynne and many others, mechanochemistry in biological systems, and the polymerization of nucleotide monophosphates on mica by Hassenkam, Damer, Mednick, and Deamer [2020]. According to this origins hypothesis, mica in micaceous clay provided an ideal environment for emerging life (1-4). Life also imitates mica in many ways. One similarity between life and mica is the presence of high concentrations of potassium ions, K+.

Hyperosmotic Adaptation of Pseudomonas protegens SN15-2 Helps Cells to Survive at Lethal Temperatures

Pseudomonas protegens is a gram-negative bacterium with an excellent biological control effect. Compared to standard cells growing in NaCl-free media, the ability of the hyperosmotic cells (450 mM NaCl) to resist high temperatures and freezing was significantly improved. It is of great significance to apply the P. protegens to elaborate on the hyperosmotic adaptation mechanism. RNA-seq was used to sequence P. protegens cultured with 0 mM and 450 mM NaCl. Comparative transcriptomic analyses of the different treatments were performed using gene ontology and the Kyoto encyclopedia of genes and genome. The results revealed that hyperosmotic stress had prominent impacts on the genes involving in multiple cellular functions. The hyperosmotic environment significantly affected carbohydrate, energy, and amino acid metabolism, as well as membrane system and cell motility. Our findings indicated that P. protegens adopted a series of approaches, including the high cytoplasmic concentrations of potassium ions and the uptake or synthesis of osmoprotectants, for surviving hyperosmotic stress. Among these, trehalose and proline synthesis appeared to be an important method to withstand prolonged hyperosmotic stress in P. protegens. These data provide crucial resource that may determine specific responses to the hyperosmotic environment in P. protegens.

Investigation of the Physiological Role of Serotonin in the Muscle Function in Planaria

In the present study, close spatial relationships between peripheral serotoninergic nerve elements and the musculature of the body in planaria Polycelis tenuis, Schmidtea mediterranea, and Girardia tigrina have been demonstrated using immunocytochemical and histochemical methods and a confocal laser scanning microscopy. Such a localization of serotoninergic neurons and their fibers indicates an important role of serotonin in the regulation of the muscle function in planaria. Investigation of the mechanisms of muscle contraction in planaria have shown that depolarization caused by high concentration of potassium ions (15–100 mM) and serotonin (10–4 –10–9 M) induced contractions of isolated muscle fibers of Procerodes littoralis. Dihydropyridine calcium channel blockers, nicardipine, nitrendipine, and nifedipine, inhibited contractions of muscles induced by potassium and serotonin suggesting the dependence of the muscle contraction on the extracellular calcium. Thapsigargin and cyclopiazonic acid decreased the number of muscle cells contracting in response to potassium ions, but did not influence the induction of the contractions by serotonin. Thus, the muscle contraction caused by serotonin did not depend on the intracellular calcium. The results provide evidence of the presence of different types of receptors and ion channels mediating the muscle contraction in planaria.

Effect of pulegone on the NLPR3 inflammasome during inflammatory activation of THP-1 cells.

Pulegone is a key active component of Schizonepeta essential oil and has been determined to have anti-inflammatory properties. However, the underlying molecular mechanisms with regard to the NLR family pyrin domain containing 3 (NLRP3) inflammasome, also known as the NALP3 inflammasome, have remained to be elucidated. NLRP3 represents a potential link between inflammation and immunity and may play possible key role in various pathologies. In the present study, the modulatory effects of pulegone on the NLRP3 inflammasome were investigated. THP-1 cells induced with phorbol myristate acetate were divided into various groups, including the Normal (control), lipopolysaccharide (LPS), LPS + ATP/nigericin, LPS + ATP/nigericin + 0.2% DMSO and pulegone (0.2, 0.1 and 0.05 mg/ml) groups. ELISA was used to detect the levels of interleukin (IL)-1β and IL-18 in the cell supernatants and the influence of potassium ions was assessed. PCR was used to determine the expression levels of NLRP3, caspase-1, IL-1β and IL-1α in the cell lysates. Furthermore, NLRP3 and apoptosis-associated speck-like protein (ASC) were detected via immunofluorescence assays and fluorescence microscopy was employed to determine the reactive oxygen species (ROS) levels in the THP-1 cells. The results indicated reduced levels of IL-18 and IL-1β in the supernatant of the cells of the pulegone groups when compared with those in the LPS + ATP/nigericin group. In addition, reduced mRNA production of inflammasome-associated genes was detected in the cell lysates after pulegone treatment. The immunofluorescence analyses indicated significantly reduced protein expression levels of NLRP3 and ASC in the pulegone groups, as well as co-localization of the NLRP3 and ASC proteins. The pulegone groups also exhibited significantly reduced ROS levels. Furthermore, a high concentration of potassium ions significantly reduced the secretion of IL-1β after induction/stimulation. In conclusion, the present study suggested that pulegone exerts its anti-inflammatory effects on LPS + ATP/nigericin-induced THP-1 cells via inhibition of NLRP3 expression, and its regulatory mechanism is associated with potassium channel and ROS pathways. It was hypothesized that pulegone first inhibits ROS signaling, to then inhibit NLRP3 expression as a downstream event. It appeared that NLRP3 may be situated further downstream and represented the link between inflammation and immunity.

Use of carbon sorbents in process of Hg-ions removal from treated wastewater

Studies on the analysis of composition of wastewater from chlorine and alkali production process, sampled at the treatment different stages, treated by electrolysis and the mercury cathode use, are presented in this paper. It is demonstrated that Hg-content range in the wastewater entering the post-treatment stage is 14.06–14.15 mg/dm3. Hg-ions sedimentation and filtration allow to reduce such content to 0.005 mg/dm3, while the final post-treatment stage with use of the anionite of АВ-17-8 type allows to achieve Hg-concentration in effluents discharged to water bodies with range of 0.001–0.002 mg/dm3. In addition to mercury, the wastewater contains relatively high concentrations of sodium, potassium, iron, aluminum and calcium ions. The main anion type in waste water is a chlorine anion; its content can be significantly reduced only after the post-treatment with the anionites. Experimental studies were carried out on the use of carbon sorbents in the process of wastewater post-treatment with regard to Hg-ions after the sedimentation and filtration stage. Tests of modified carbon sorbents for Hg-ion removal from standardized test solutions with different concentrations were carried out under static conditions. It was demonstrated that the higher post-treatment degrees were achieved with active carbons of АГ-3 and АГ-5 types, modified with HNO3 and MnS. Purification degree was 97–99% with 1,0-11,8 mg/dm3 Hg-concentration in treated solutions. Usage effectiveness of active carbons of АГ-3 and АГ-5 types (produced at “Sorbent JSC” Perm, Russia), modified with active compounds, was demonstrated.

Ground Water Quality of Selected Areas of Punjab and Sind Provinces, Pakistan: Chemical and Microbiological Aspects

The assessment of groundwater is essential for the estimation of suitability of water for safe use. An attempt has been made to study the groundwater of selected areas of Punjab (Sheikhupura & Sahiwal) and Sindh (Sindh, Jawar Dharki and Dharki), Pakistan. The results indicate that pH, color and odor were all within limits of WHO that is pH ranges 6.5–8.5, colorless and odorless, respectively. The high values of suspended solids were observed in the Sindh-1 and Dharki samples. Microbiologically only Sahiwal and Jawar Dharki were found fit for drinking purpose. Trace metals analysis of Sheikhupura-1 and Sindh-1 showed that values do not fall within limits of WHO for Iron. The ionic concentration analysis showed that high bicarbonate (HCO3-), ions are present in the samples of Sahiwal and Dharki; Sindh-1 and Jawar Dharki samples showed very high concentration for chloride ions, all samples were satisfactory level for sulphate (SO42-), sodium, magnesium and phosphate ions except samples of Sindh-1 and Jawar Dharki. High concentration of calcium and potassium ions was observed in samples of Sindh-1, while all other samples were found fit for drinking purposes in respect of nitrate, nitrite and ammonium ions. The high concentration of Fluoride was found only in Sheikhupura-2 samples.

Anomalous X-ray diffraction studies of ion transport in K+ channels

Potassium ion channels utilize a highly selective filter to rapidly transport K+ ions across cellular membranes. This selectivity filter is composed of four binding sites which display almost equal electron density in crystal structures with high potassium ion concentrations. This electron density can be interpreted to reflect a superposition of alternating potassium ion and water occupied states or as adjacent potassium ions. Here, we use single wavelength anomalous dispersion (SAD) X-ray diffraction data collected near the potassium absorption edge to show experimentally that all ion binding sites within the selectivity filter are fully occupied by K+ ions. These data support the hypothesis that potassium ion transport occurs by direct Coulomb knock-on, and provide an example of solving the phase problem by K-SAD.

Lithium Ion Recognition with Nanofluidic Diodes through Host-Guest Complexation in Confined Geometries.

The lithium ion recognition is receiving significant attention because of its application in pharmaceuticals, lubricants and, especially, in energy technology. We present a nanofluidic device for specific lithium ion recognition via host-guest complexation in a confined environment. A lithium-selective receptor molecule, the aminoethyl-benzo-12-crown-4 (BC12C4-NH2), is designed and functionalized on single conical nanopores in polyethylene terephthalate (PET) membranes. The native carboxylic acid groups on the pore walls are covalently linked with the crown ether moieties and the process is monitored from the changes in the current-voltage ( I- V) curves. The B12-crown-4 moieties are known to specifically bind with lithium ions and when the modified pore is exposed to different alkali metal chloride solutions separately, significant changes in the ion current and rectification are only observed for lithium chloride. This fact suggests the generation of positively charged B12C4-Li+ complexes on the pore surface. Furthermore, the nanofluidic diode is able to recognize the lithium ion even in the presence of high concentrations of potassium ions in the external electrolyte solution. Thus, this nanodevice suggests a strategy to miniaturize nanofluidic porous systems for efficient recognition, extraction, and separation of lithium from raw materials.

Movement of Potassium Ions inside KcsA in the High Concentration Regime using a Molecular Dynamics Simulation

The selectivity and conduction specificity of the KcsA channel toward potassium ions is crucial to the activity of this protein and this channel is intricately associated with several osmotic regulation and neuronal signaling processes. Despite multi-ion characteristics, the selective conduction behavior of KcsA is controlled by the size and distance specific electrostatic interaction between the selected residues and the potassium ions. The mechanism describing the movement of potassium ions in the channel and the conformational changes to KcsA that facilitate ion movement were investigated by a molecular dynamics (MD) simulation. In this study, we analyze the movement of potassium ions and water molecules at various time intervals during a 90 ns molecular dynamics simulation in the high potassium ion concentration regime and in the absence of the voltage. Examination of specific (3.6, 17.3, 43.38 and 43.44 ns) simulation periods revealed that key residues in the selectivity filter of KcsA influence the movement of potassium ions in the channel.

Aerosol composition and microstructure in the smoky atmosphere of Moscow during the August 2010 extreme wildfires

This is a comprehensive study of the physicochemical characterization of multicomponent aerosols in the smoky atmosphere of Moscow during the extreme wildfires of August 2010 and against the background atmosphere of August 2011. Thermal–optical analysis, liquid and ion chromatography, IR spectroscopy, and electron microscopy were used to determine the organic content (OC) and elemental content (EC) of carbon, organic/inorganic and ionic compounds, and biomass burning markers (anhydrosaccharides and the potassium ion) and study the morphology and elemental composition of individual particles. It has been shown that the fires are characterized by an increased OC/EC ratio and high concentrations of ammonium, potassium, and sulfate ions in correlation with an increased content of levoglucosan as a marker of biomass burning. The organic compounds containing carbonyl groups point to the process of photochemical aging and the formation of secondary organic aerosols in the urban atmosphere when aerosols are emitted from forest fires. A cluster analysis of individual particles has indicated that when the smokiest atmosphere is characterized by prevailing soot/tar ball particles, which are smoke-emission micromarkers.

Thermophilic anaerobic digestion of cheese whey: Coupling H2 and CH4 production

The thermophilic anaerobic digestion of cheese whey was evaluated using a single and two stage configuration (H2–CH4) in a sequencing batch reactor (SBR). The single stage process presented stable performance with a specific methane production (SMP) of 314.5 ± 6.6 L CH4 kg−1 CODfeed (Chemical oxygen demand) at a hydraulic retention time (HRT) of 8.3 days. On the contrary, the two stage process presented instabilities at an HRT of 12.5 days with acid accumulation being observed in the methanogenesis phase at an earlier stage. This behaviour was indicative of process inhibition by high concentrations of sodium and potassium ions as a consequence of pH control during the H2 producing stage. In spite of this phenomenon, this condition attained the highest SMP value (340.4 ± 40 L CH4 kg−1 CODfeed). The performance of the anaerobic digestion process was also analysed by means of Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. The two stage process showed higher content in triacylglycerol groups probably associated with changes in archaeal lipid complexes as a microbial response to a higher salinity environment.

Enhanced corneal wound healing with hyaluronic acid and high‐potassium artificial tears

BackgroundThe aim of this study was to investigate the therapeutic role of preservative‐free artificial tears containing hyaluronic acid and high potassium ion concentration (HA/high‐K artificial tears) on mechanically scraped or alkali‐induced corneal epithelial defects in rats.MethodsWe created mechanically scraped epithelial defects on the corneas of 24 Sprague‐Dawley (SD) rats (three groups of eight rats) and alkali‐induced epithelial defects on the corneas of 27 SD rats (three groups of nine rats). Then we applied topical 0.3 per cent or 0.15 per cent HA/high‐K artificial tears four times daily for 1.5 days and compared its effect with that of topical phosphate buffered saline (PBS). The fluorescein staining analysis and histological examination were performed immediately after and at 12, 24 and 36 hours after injury.ResultsIn the mechanical scraping model, the areas of fluorescein staining in the eyes after topical application of 0.3 per cent HA/high‐K artificial tears were significantly smaller than those after PBS treatment at 12 and 24 hours after injury. At 36 hours, the staining areas of both 0.3 per cent and 0.15 per cent HA/high‐K artificial tears‐treated eyes were found to be significantly smaller than those of the PBS‐treated eyes. In the alkali burn model, the promotion of corneal epithelial wound healing after treatment with 0.3 per cent and 0.15 per cent HA/high‐K artificial tears was not significantly different compared to that after treatment with PBS.ConclusionHyaluronic acid and high potassium ion concentration artificial tears promoted corneal epithelial wound healing in the mechanical scraping model; however, in the alkali burn model, no significant beneficial effect of this treatment was observed.