High Salt Solution Research Articles

Oxidation of 4-hydroxybenzoic acid in strongly alkaline and high-salt solutions via ultrasonic-assisted ozone: Helping radioactive waste disposal and environmental safety

4-Hydroxybenzoic acid (4-HBA), as a gibbsite dissolution inhibitor and typical personal care products (PPCPs), seriously troubles radioactive waste disposal and environmental safety. This work studies the degradation mechanism of 4-HBA in ultrasonic-assisted ozonation in strongly alkaline and high-salt solutions, and comprehensively evaluates its environmental lifetime. Ultrasonic can significantly increase the effect of ozone by 1.52 times, making the degradation rate of 4-HBA reach 63.49 % within 60 min. The better electrochemical performance indicates that the redox reaction between US/O3 system and 4-HBA is more prominent. Experimental analysis and density functional theory (DFT) calculations show that the effects of OH, 1O2, O2−, and others on the degradation of 4-HBA are 56.6 %, 17.8 %, 22.1 %, and 3.5 % respectively, and HO3 is the most important precursor for OH evolution. Mechanistic exploration and DFT calculations show that degradation behavior of 4-HBA in strongly alkaline and high-salt solutions, i.e., decarboxylation reaction, ring opening, hydroxylation, aldol condensation, and hydrogenation, is significantly different from acidic or neutral solutions. Based on the environmental lifetime assessment of the intermediate product, US/O3 technology can help reduce the toxicity of 4-HBA. The US/O3 process is used to remove 4-HBA from strongly alkaline and high-salt solutions, which has huge potential economic benefits in the fields of nuclear waste chemistry and environment.

Soy lysolecithin prevents hypertension and cognitive impairment induced in mice by high salt intake by inhibiting intestinal inflammation

High salt (HS) intake induces hypertension and cognitive impairment. Preventive strategies include against dietary supplements. Soybean lecithin is a widely used phospholipid supplement. Lysolecithin is important in cell signaling, digestion, and absorption. This study aimed to investigate the effects of lysophosphatidylcholine containing >70% of the total phospholipids (LPC70), on hypertension and cognitive impairment induced in mice by HS intake. Mice were provided with HS solution (2% NaCl in drinking water) with or without LPC70 for 12 weeks. Blood pressure, cognitive function, and inflammatory response of intestine were determined. Hypertension and impaired object recognition memory induced by HS intake were implicated with increased inducible nitric oxide synthase in the small intestine and tau hyperphosphorylation in the prefrontal cortex. LPC70 treatment prevented cognitive impairment by suppressing inducible nitric oxide synthase and tau hyperphosphorylation. LPC70 may be valuable as a functional food component in preventing HS-induced cognitive impairment.

Using AuNPs-DNA Walker with Fluorophores Detects the Hepatitis Virus Rapidly.

Viral hepatitis is a systemic infectious diseases caused by various hepatitis viruses, primarily leading to liver damage. It is widely prevalent worldwide, with hepatitis viruses categorized into five types: hepatitis A, B, C, D, and E, based on their etiology. Currently, the detection of hepatitis viruses relies on methods such as enzyme-linked immunosorbent assay (ELISA), immunoelectron microscopy to observe and identify viral particles, and in situ hybridization to detect viral DNA in tissues. However, these methods have limitations, including low sensitivity, high error rates in results, and potential false negative reactions due to occult serum infection conditions. To address these challenges, we have designed an AuNPs-DNA walker method that uses gold nanoparticles (AuNPs) and complementary DNA strands for detecting viral DNA fragments through a colorimetric assay and fluorescence detection. The DNA walker, attached to gold nanoparticles, comprises a long walking strand with a probe sequence bound and stem-loop structural strands featuring a modified fluorescent molecule at the 3' end, which contains the DNAzyme structural domain. Upon the addition of virus fragments, the target sequence binds to the probe chains. Subsequently, the long walking strand is released and continuously hybridizes with the stem-loop structural strand. The DNAzyme undergoes hydrolytical cleavage by Mg2+, breaking the stem-loop structural strand into linear single strands. As a result of these structural changes, the negative charge density in the solution decreases, weakening spatial repulsion and rapidly reducing the stability of the DNA walker. This leads to aggregation upon the addition of a high-salt solution, accompanied by a color change. Virus typing can be performed through fluorescence detection. The innovative method can detect DNA/RNA fragments with high specificity for the target sequence, reaching concentrations as low as 1 nM. Overall, our approach offers a more convenient and reliable method for the detection of hepatitis viruses.

Identification of a novel neurovirulence factor encoded by the cryptic orphan gene UL31.6 of herpes simplex virus 1.

Although the herpes simplex virus type 1 (HSV-1) genome was thought to contain approximately 80 different protein coding sequences (CDSs), recent multi-omics analyses reported HSV-1 encodes more than 200 potential CDSs. However, few of the newly identified CDSs were confirmed to be expressed at the peptide or protein level in HSV-1-infected cells. Furthermore, the impact of the proteins they encode on HSV-1 infection is largely unknown. This study focused on a newly identified CDS, UL31.6. Re-analyzation of our previous chemical proteomics data verified that UL31.6 was expressed at the peptide level in HSV-1-infected cells. Antisera raised against a viral protein encoded by UL31.6 (pUL31.6) reacted with a protein with an approximate molecular mass of 37 kDa in lysates of Vero cells infected with each of three HSV-1 strains. pUL31.6 was efficiently dissociated from virions in high-salt solution. A UL31.6-null mutation had a minimal effect on HSV-1 gene expression, replication, cell-to-cell spread, and morphogenesis in Vero cells; in contrast, it significantly reduced HSV-1 cell-to-cell spread in three neural cells but not in four non-neural cells including Vero cells. The UL31.6-null mutation also significantly reduced the mortality and viral replication in the brains of mice after intracranial infection, but had minimal effects on pathogenic manifestations in and around the eyes, and viral replication detected in the tear films of mice after ocular infection. These results indicated that pUL31.6 was a tegument protein and specifically acted as a neurovirulence factor by potentially promoting viral transmission between neuronal cells in the central nervous system.IMPORTANCERecent multi-omics analyses reported the herpes simplex virus type 1 (HSV-1) genome encodes an additional number of potential coding sequences (CDSs). However, the expressions of these CDSs at the peptide or protein levels and the biological effects of these CDSs on HSV-1 infection remain largely unknown. This study annotated a cryptic orphan CDS, termed UL31.6, an HSV-1 gene that encodes a tegument protein with an approximate molecular mass of 37 kDa, which specifically acts as a neurovirulence factor. Our study indicates that HSV-1 proteins important for viral pathogenesis remain to be identified and a comprehensive understanding of the pathogenesis of HSV-1 will require not only the identification of cryptic orphan CDSs using emerging technologies but also step-by-step and in-depth analyses of each of the cryptic orphan CDSs.

Comparison between capillary electrophoresis and fluorescence anisotropy competitive immunoassay for glucagon.

Glucagon plays a crucial role in regulating glucose homeostasis; unfortunately, the mechanisms controlling its release are still unclear. Capillary electrophoresis (CE)- and fluorescence anisotropy (FA)-immunoassays (IA) have been used for online measurements of hormone secretion on microfluidic platforms, although their use in glucagon assays is less common. We set out to compare a glucagon-competitive IA using these two techniques. Theoretical calibration curves were generated for both CE- and FA-IA and results indicated that CE-IA provided higher sensitivity than FA-IA. These results were confirmed in an experiment where both assays showed limits of detection (LOD) of 30nM, but the CE-IA had ∼300-fold larger sensitivity from 0 to 200nM glucagon. However, in online experiments where reagents were mixed within the device, the sensitivity of the CE-IA was reduced ∼3-fold resulting in a higher LOD of 70nM, whereas the FA-IA remained essentially unchanged. This lowered sensitivity in the online CE-IA was likely due to poor sampling by electroosmotic flow from the high salt solution necessary in online experiments, whereas pressure-based sampling used in FA-IA was not affected. We conclude that FA-IA, despite lowered sensitivity, is more suitable for online mixing scenarios due to the ability to use pressure-driven flow and other practical advantages such as the use of larger channels.

Effect of combined microbial and stress corrosion on 7075 aluminum alloy in high salinity environment

The study investigates the impact of the combination of Gram-positive bacteria Bacillus subtilis (B. subtilis) and tensile stress on the surface corrosion of 7075 aluminum alloy (AA7075) in a high-salt solution environment. The change in PH value caused by the growth curve of bacteria was analyzed for corrosion factors. Scanning electron microscopy (SEM) and ultra-depth 3D microscopy (DOF) were used to compare the surface morphology, elements and corrosion of the samples. The presence of a biofilm reduces the corrosion rate by 0.005 ± 0.0004 mm/y and the application of a constant load results in an increase in the corrosion rate to 0.26 ± 0.013 mm/y. The applied stress leads to the disruption of both the biofilm and oxide film on the metal surface, causing a significant reduction in the impedance isolation effect, and resulting in an expansion of the average diameter and depth of the corrosion pit by 372.21 and 29.5 µm, respectively. In electrochemical impedance testing, there is an approximately 7.01×103 Ω increase in impedance value when exposed to B. subtilis environment; conversely, under stress conditions, there is a decrease by 4.02×103 Ω with B. subtilis present. The corrosion current density has increased fourfold to reach 9.15×10−6 (uA/cm2). This suggests that the combination of bacterial and stress can have a complex and detrimental impact on the corrosion behavior of aluminum alloys in high-salt environments.

Bio-inspired superhydrophobic fiber membrane for oil-water separation and non-destructive transport of liquids in corrosive environments

Conventional polymer separation membranes or coatings suffer from poor separation performance and serious failure in highly corrosive environments, due to their low chemical and mechanical stability. Herein, a simple electrospraying and electrospinning strategy was used to prepare flexible superhydrophobic carbon fiber membranes (FSCFM). The wettability of FSCFM was improved by forming a lotus leaf-like hierarchical rough structure on its surface. The FSCFM exhibited an excellent permeation flux of immiscible oil-water mixtures (up to 15,800 L m−2 h−1) and water-in-oil emulsions (over 5500 L m−2 h−1), while the separation efficiencies were always kept at more than 99 % after 25 consecutive separations. Even in corrosive environments, its separation performance did not show any degradation. Notably, except for recovering floating oil under external driving forces with excellent cyclic stabilities, FSCFM was also able to transport various corrosive solutions with high efficiencies (99.9 %). After multiple mechanical damages and bending cycles, the FSCFM remained superhydrophobic. It could also maintain its repellency in strong acids/bases, high salt solutions and even under high-temperature environments (94.5 °C). These superior properties make it a strong candidate for oil-water mixture/emulsion separation and non-destructive transport of highly corrosive fluids.

Ultrasound catalytic ozonation to remove 5-hydroxy-1,3-phthalic acid from strongly alkaline and high-salt solutions: Aiding nuclear waste disposal and human health

As a typical precipitation inhibitor and the main component of plasticizers, 5-hydroxy-1,3-phthalic acid (5-HPA) seriously threatens the nuclear waste disposal and human health. OH, 1O2, and O2− induced by the ultrasound catalytic ozonation (US/O3) process achieves a removal rate of 60.67 % of 5-HPA in strongly alkaline and high-salt solutions within 60 min, which is significantly higher than the O3 alone process. This technology is highly resistant to inorganic anions that coexist in industrial production, but the mineralization process is inhibited. Ozone utilization and mass transfer are significantly improved by ultrasound, including reducing the ozone bubble size by 38 %, increasing the ozone utilization rate from 52 % to 75 %, increasing the volumetric mass transfer coefficient by 61 %, and increasing the specific interfacial area by 60 %, reducing the molar ratio of ozone to TOC from 0.45 to 0.23. Through a combination of Density functional theory (DFT) and GC–MS, four pathways for removing 5-HPA are clearly proposed, which are significantly different from the evolution behavior in acidic systems. The US/O3 system has significant application potential in reducing the threat of 5-HPA to nuclear waste disposal and human health.

Reversible capture and release of I2 with dechlorinated porous organic polymer

In recent years, porous organic polymers (POPs) possess a remarkable potential as adsorbents for heavier halogen (I2 and Br2) capture in the fields of environmental treatment and industrial production. How to improve iodine adsorption properties through efficient molecular structure design is still worth exploring. In this work, a novel nitrogen-rich POP, defined as POP-TT, for iodine capture is designed and easily obtained by reacting 2,4,6-trichloro-1,3,5-triazine (TCT) and tris(4-aminophenyl) amine (TAPA) with the aid of dechlorination agent under mild condition, inspired by the significant enhancement of iodine capture with N-rich heterocyclic structure. The proposed POP-TT shows good stability and porosity even in high-salt solutions. Profiting from the nitrogen-rich skeleton and phenyl groups of POP-TT and strong charge-transfer interaction between polymer framework and adsorbed iodine, the proposed POP-TT exhibits excellent affinity with uptake capacity of 4.62 g g−1 for iodine vapor and removal efficiency of 86.8 % for iodine aqueous solution. Good retention behavior and recycling capacity are also observed for POP-TT. This work provides a practical guide for designing heavier halogen adsorbents by using dechlorinated porous organic polymers.

Ultrahigh separation property of GO membrane for dissolved organic compound in high-salt brine

The membrane separation technology for the removal of dissolved organic compounds still faces numerous challenges in concentrated salt solution. In this work, the GO/PES membrane was successfully fabricated only adjusting the pH value without any cross-linking agent. The morphology, surface charge distribution, and separation performances were characterized in detail. Results demonstrated the GO/PES membrane exhibited excellent separation performances for tributyl phosphate, sulfonated kerosene and bis(2-ethylhexyl) phosphate with the corresponding flux of 630, 560 and 600 L‧m−2‧h−1, and separation efficiency of 93.1 %, 95.6 % and 96.5 %, respectively, exhibiting both high selectivity and permeability. Meanwhile, the GO/PES membrane exhibited almost 100 % separation efficiency with flux of 1430 L‧m−2‧h−1 for methylene blue solution. Impressively, the GO/PES membrane showed ultrahigh separation efficiency for 200 Da without influences on ions when the salt content was 327 g‧L−1. Furthermore, the GO/PES membrane exhibited robust structural stability and excellent separation performances, which can endure 2000 times folds and corrosion in HCl, NaOH and NaCl for two weeks without separation performances decline. This study highlighted the broad application prospects in the treatment fields of high-salt solution.

Effects of High Temperature and Different Salt Solutions on Basalt Fiber-Reinforced Composites’ Bonded Joint Durability Impact

Fiber-reinforced composites are widely used in industrial development due to their excellent performance, and the study of basalt fiber-reinforced resin (BFRP) as a new type of economical and environmentally friendly material is highly valued, since harsh environments can affect the durability of bonded joints. In this paper, the Araldite® 2015 adhesive for BFRP–BFRP single lap joints (SLJs) was selected as the subject of study and the joints were analyzed in aging experiments in three environments: deionized water (DW), 3.5% NaCl solution, and 5% NaCl solution at 80 °C for 0 days (no aging), 10 days, 20 days, and 30 days. Using Fick’s second law to describe water absorption in joints and materials, the comparison shows that the water absorption in the joints occurs primarily in the adhesive. Differential scanning calorimetry (DSC) was used to characterize the decrease in the glass transition temperature (Tg) of the adhesive at each failure point, and the thermogravimetric analysis (TGA) tests showed that moisture and heat led to the degradation of the polymer material in the joint. The failure strength of the joints in quasi-static tensile tests was positively correlated with the moisture content of the solution, and the changes in the absorption peaks of the functional groups of the adhesive after aging were observed. The comprehensive macro-micro failed section analysis showed that the water molecules damage the chemical properties of the adhesive, meaning that the adhesive and BFRP binding ability is decreased. The proportion of failure section tear decreased with the extension of the aging time, and a high temperature induced water evaporation and an adhesive post-curing reaction. The change in the failure mode is a result of the combined effect of the post-curing effect and hydrolysis reaction, which is validated by the results of the Fourier infrared spectroscopy (FTIR). This study contributes to an in-depth understanding of the effect of moisture and heat on the residual properties of bonded joints.

Electrochemical dissolution behavior and electrochemical jet machining characteristics of titanium alloy in high concentration salt solution

Electrochemical dissolution behavior and electrochemical jet machining characteristics of titanium alloy in high concentration salt solution

Investigation into Na and Cs activity coefficients in high salt solutions to support Cs removal in Hanford tank waste

Abstract The treatment of Hanford tank waste is one of the most technically challenging environmental cleanup activities for the U.S. Department of Energy to date. To expedite the processing of liquid waste stored in underground tanks in southeastern Washington state, it is necessary to remove the significant dose contributor, 137Cs. Toward this effort, ion exchange with crystalline silicotitanate (CST) has been employed as part of the Tank Side Cesium Removal system. The model used to predict Cs exchange onto CST was developed using activity coefficients calculated from the Bromley equation. A series of batch contact tests that varied in [Na] were conducted to look at the impact of Na concentration on Cs distribution. Experimental distribution ratios (K d) were compared to the distribution ratios predicted using three different activity coefficient models: (1) commercially available HSC software, (2) the Bromley equation, and (3) a simplified approach adapted from Marcos-Arroyo et al. Ultimately, the Bromley method underpredicted the effect of ionic strength on the Na activity coefficient (γ Na+), HSC overestimated the impact of ionic strength on the expected performance due to the Cs activity coefficient (γ Cs+), but the simplified approach predicted the experimental K d values quite well in a binary matrix. Expansion of this approach in complex matrices is necessary for application to Hanford tank waste.

The cryo-EM 3D image reconstruction of isolated Lethocerus indicus Z-discs.

The Z-disk of striated muscle defines the ends of the sarcomere, which repeats many times within the muscle fiber. Here we report application of cryoelectron tomography and subtomogram averaging to Z-disks isolated from the flight muscles of the large waterbug Lethocerus indicus. We use high salt solutions to remove the myosin containing filaments and use gelsolin to remove the actin filaments of the A- and I-bands leaving only the thin filaments within the Z-disk which were then frozen for cryoelectron microscopy. The Lethocerus Z-disk structure is similar in many ways to the previously studied Z-disk of the honeybee Apis mellifera. At the corners of the unit cell are positioned trimers of paired antiparallel F-actins defining a large solvent channel, whereas at the trigonal positions are positioned F-actin trimers converging slowly towards their (+) ends defining a small solvent channel through the Z-disk. These near parallel F-actins terminate at different Z-heights within the Z-disk. The two types of solvent channel in Lethocerus are similar in size compared to those of Apis which are very different in size. Two types of α-actinin crosslinks were observed between oppositely oriented actin filaments. In one of these, the α-actinin long axis is almost parallel to the F-actins it crosslinks. In the other, the α-actinins are at a small but distinctive angle with respect to the crosslinked actin filaments. The utility of isolated Z-disks for structure determination is discussed.

Sustainable and highly-stable carbon dots from cellulose as a fluorescent reference for visual ratiometric pH detection

Fluorescent materials, including organic molecules and quantum dots, usually respond to the environmental changes, such as acidity and basicity. It is challenging to construct highly-stable fluorescent materials. In this work, we fabricated novel carbon dots (CDs) with a high stability and a high quantum yield by using a solvothermal process, in which cellulose was the green precursor and 1-allyl-3-methylimidazolium chloride (AmimCl)/N,N-dimethylformamide (DMF) was the solvent. The resultant CDs had the cationic imidazolium groups on their surface. As a result, they exhibited the excellent fluorescence stability in strong-acidic, strong-basic and high salt solutions. In addition, the CDs also presented a good resistance to the photobleaching under strong UV irradiation conditions. The highly stable CDs can be utilized as a fluorescent reference to significantly improve the responsiveness of the fluorescent materials. For example, the CDs were combined with cellulose acetate fluorescein isothiocyanate (CA-FITC) to obtain a series of ratiometric probes, which can visually detect pH values with a higher sensitivity. Furthermore, based on the outstanding processability and formability of cellulose derivatives, the CDs/CA-FITC was easily fabricated into responsive fluorescent coatings, films, and inks, indicating a huge potential in visual detection, solid-state luminescence, and anti-counterfeiting.

Salt-resistance holocellulose-based solar steam evaporator for desalination brine water

Interfacial solar-powered water evaporation is a cost-effective and sustainable approach using solar energy for seawater desalination. Nevertheless, salt accumulation during solar desalination generally restricts the widespread application of solar vapor generation. Herein, taking merits of the excellent hydrophilicity and inherent porosity of holocellulose (HC), An excellent salt-resistant solar steam evaporator for long-term interfacial solar water desalination was fabricated by decorating polypyrrole (PPy) on the surface of HC. Due to the broadband light absorbance of PPy and the superhydrophilic HC substrate, the PPy-HC evaporator exhibited a high evaporation rate of 1.45 kg m−2 h−1 and conversion efficiency of 93.4 % in a 5 wt% NaCl solution under one sun illumination. Importantly, the evaporator presented superior salt-resistance and stability during long-term cycling test in high salinity brine. This work reveals the key role of superhydrophilicity and water transportation capability in high salt solution solar-driven desalination. Thus, this work provides an effective approach to address the issue of salt accumulation of the traditional evaporator, demonstrating its great potential for real-world solar-driven seawater desalination.

Compression Behavior of Rubber–Bentonite Mixture under Different Salinities

This study investigated the engineering properties of a rubber–bentonite mixture under different salt solution concentrations, mass ratios, and consolidation pressures. In addition, the effects of different solute ion concentrations on the compression index of the samples were compared. The results showed that the compression coefficient could be reduced effectively by increasing the weight percentage of rubber without being affected by the salt solution. However, with the increase in the salt solution concentration, the compression coefficient of mixed materials with different mass ratios increased, and when the salt solution concentration exceeded 0.5 mol/L, the compression coefficient increased more obviously. In a 0.1 mol/L NaCl solution, the addition of different levels of rubber could increase the compression modulus of the mixed material and reduce the compression ratio of the mixed material. This showed that in an environment with a low salt solution concentration, adding rubber into the mixed material could enhance its compressive deformation resistance. However, when the rubber content exceeded 50%, significant pores appeared in the sample, and the effect of high salt solution concentration intensified. The rubber content also had an effect on the swelling properties of soil, and the degradation of rubber in the salt solution showed reduced mechanical properties. This emphasizes the need to consider the stability and resistance of saline–alkali areas to salt erosion.

Three-phase partitioning constructed by pH-responsive deep eutectic solvents and sugars for purification of radish (Raphanus sativus L.) peroxidase

Ammonium sulfate and t-butanol are widely used in conventional three-phase partitioning (TPP); however, their use is not eco-friendly. In this study, a novel TPP was developed using pH-responsive deep eutectic solvents (DESs) and sugars as substitutes for t-butanol and ammonium sulfate, respectively. This TPP was further used for the separation and purification of radish (Raphanus sativus L.) peroxidase (POD). DES-3 (dodecanoic acid: decanoic acid = 1:1) and sucrose were selected as optimal phase-forming components. Single-factor experiments were performed to investigate the factors influencing the TPP process, and three major factors (sucrose concentration, extraction time, and extraction temperature) were optimized by response surface methodology (RSM). Under the optimized conditions, the POD recovery and purification fold reached 101.66% and 11.56, respectively. Cyclic experiments confirmed the retrievability of DESs. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the novel TPP had better purification efficiency than the traditional TPP. The method proposed in this study is more efficient than conventional TPP, and it does not require the use of organic solvents and high concentration salt solutions. Therefore, this method is promising in the application of TPP.

Sugarcane inspired polydopamine @ attapulgite-based aerogels with vertical pore structure for solar-driven steam generation

Desalination using solar-driven photothermal evaporators (SPEs) is of great significance for solving mankind's current shortage of fresh water. Herein, inspired by the vascular bundles for the directed and rapid transport of water and organic pollution such as inorganic salts in the vascular system of sugarcane, a polydopamine (PDA) @ attapulgite (ATP) based biomimetic aerogel (named as PAS aerogels) was prepared for efficient desalination. In PAS aerogels, the ATP gives the aerogel excellent mechanical properties, whereas the PDA gives the aerogel excellent light absorption properties. In the wet state, PAS aerogels have low thermal conductivity (0.24 W ∙ m−1∙ K−1) and low apparent density (0.13 g ∙ cm−3). Indicating that the photothermal evaporation rate of PAS-1.5 aerogel is 1.71 kg ∙ m−2∙ h−1 in pure water under 1 sun irradiation. Meanwhile, it can maintain excellent evaporation performance even in high salt solution with 20% concentration (about 1.50 kg ∙ m−2∙ h−1). Owing to the vertical pore structure of the aerogel, which is similar to that of sugarcane transport tissues, the aerogel has both an adequate supply of water and excellent salt tolerance. Furthermore, outdoor experiment of Yellow Sea water evaporation demonstrates its feasibility in the actual production of desalination.

High salt induces cognitive impairment via the interaction of the angiotensin II-AT1 and prostaglandin E2-EP1 systems.

High salt (HS) intake has been associated with hypertension and cognitive impairment. It is well known that the angiotensin II (Ang II)-AT1 receptor and prostaglandin E2 (PGE2)-EP1 receptor systems are involved in hypertension and neurotoxicity. However, the involvement of these systems in HS-mediated hypertension and emotional and cognitive impairments remains unclear. Mice were loaded with HS solution (2% NaCl drinking water) for 12 weeks, and blood pressure was monitored. Subsequently, effects of HS intake on emotional and cognitive function and tau phosphorylation in the prefrontal cortex (PFC) and hippocampus (HIP) were investigated. The involvement of Ang II-AT1 and PGE2-EP1 systems in HS-induced hypertension and neuronal and behavioural impairments was examined by treatment with losartan, an AT1 receptor blocker (ARB), or EP1 gene knockout. We demonstrate that hypertension and impaired social behaviour and object recognition memory following HS intake may be associated with tau hyperphosphorylation, decreased phosphorylation of Ca2+ /calmodulin-dependent protein kinase II (CaMKII), and postsynaptic density protein 95 (PSD95) expression in the PFC and HIP of mice. These changes were blocked by pharmacological treatment with losartan or EP1 receptor gene knockout. Our findings suggest that the interaction of Ang II-AT1 receptor and PGE2-EP1 receptor systems could be novel therapeutic targets for hypertension-induced cognitive impairment.