High NaCl Concentrations Research Articles

Changes in Photosystem II Complex and Physiological Activities in Pea and Maize Plants in Response to Salt Stress.

Salt stress significantly impacts the functions of the photosynthetic apparatus, with varying degrees of damage to its components. Photosystem II (PSII) is more sensitive to environmental stresses, including salinity, than photosystem I (PSI). This study investigated the effects of different salinity levels (0 to 200 mM NaCl) on the PSII complex in isolated thylakoid membranes from hydroponically grown pea (Pisum sativum L.) and maize (Zea mays L.) plants treated with NaCl for 5 days. The data revealed that salt stress inhibits the photochemical activity of PSII (H2O → BQ), affecting the energy transfer between the pigment-protein complexes of PSII (as indicated by the fluorescence emission ratio F695/F685), QA reoxidation, and the function of the oxygen-evolving complex (OEC). These processes were more significantly affected in pea than in maize under salinity. Analysis of the oxygen evolution curves after flashes and continuous illumination showed a stronger influence on the PSIIα than PSIIβ centers. The inhibition of oxygen evolution was associated with an increase in misses (α), double hits (β), and blocked centers (SB) and a decrease in the rate constant of turnover of PSII reaction centers (KD). Salinity had different effects on the two pathways of QA reoxidation in maize and pea. In maize, the electron flow from QA- to plastoquinone was dominant after treatment with higher NaCl concentrations (150 mM and 200 mM), while in pea, the electron recombination on QAQB- with oxidized S2 (or S3) of the OEC was more pronounced. Analysis of the 77 K fluorescence emission spectra revealed changes in the ratio of the light-harvesting complex of PSII (LHCII) monomers and trimers to LHCII aggregates after salt treatment. There was also a decrease in pigment composition and an increase in oxidative stress markers, membrane injury index, antioxidant activity (FRAP assay), and antiradical activity (DPPH assay). These effects were more pronounced in pea than in maize after treatment with higher NaCl concentrations (150 mM-200 mM). This study provides insights into how salinity influences the processes in the donor and acceptor sides of PSII in plants with different salt sensitivity.

Differential responses of six Casuarina species to NaCl seed priming and salt stress during germination and early seedling growth

The degradation of salinized soils is imposing a steady decline in productivity, leading to significant socio-economic and environmental repercussions. As a promising solution for revitalizing depleted soil potential, the cultivation of salt-tolerant plants such as Casuarina emerges as a viable approach. This study delves into this prospect by evaluating six Casuarina species to discern their levels of tolerance to varying concentrations of NaCl, particularly in the initial stages of germination and seedling growth. The imposition of salt stress instigated a reduction in both germination capacity and speed. High variability in salt tolerance was observed between the tested species. Notably, the final germination percentages at 100 mM NaCl unveiled considerable disparities: C. torulosa, C. tenuissima, and C. stricta exhibited percentages of 33%, 19%, and 10%, respectively, while C. cunninghamiana, C. equisetifolia, and C. glauca showcased higher germination rates at 63%, 62%, and 55%, respectively. Furthermore, the increase of the recovery rate with high NaCl concentration confirmed that the salinity caused only an osmotic effect and not a toxic one on the studied species. Additionally, the adoption of seed priming showcased marked enhancements in germination rates across all NaCl concentrations, effectively expediting the germination process. In response to salinity stress, reductions were noted in root length (RL), and shoot length (SL). All germination parameters and the computation of the salt tolerance index (STI) facilitated the classification of the six Casuarina species in a descending order of salinity tolerance: C. cunninghamiana Miq. > C. equisetifolia L. > C. glauca Sieb. > C. torulosa Ait. > C. tenuissima Sieb. > C. stricta Ait.

Anionic Dye Removal with a Thin Cationic Polyaniline Coating on Cellulosic Biomaterial.

This paper reports the development of novel adsorbent materials using polyaniline (PANI) grafted onto Posidonia (POS) fibers, aimed at efficiently removing phenol red (PSP), an anionic dye, from aqueous solutions. The synthesis involved the copolymerization of aniline grafted on the surface of the POS and aniline monomer in solution, resulting in a chemically bound thin PANI layer on the POS bioadsorbent. Structural characteristics and binding affinities of these adsorbents with PANI under its emeraldine salt (POS@PANI-ES) or emeraldine base (POS@PANI-EB) forms are reported. The rapid adsorption kinetics observed are attributed to enhanced accessibility to PANI adsorption sites on the POS surface. The binding percentages of PSP to POS@PANI-ES and POS@PANI-EB materials were found to be 97 and 50%, respectively, after 15 min of contact time. The Langmuir model for localized adsorption sites and the Volmer model for nonlocalized adsorption as a mobile layer were fitted to the experimental adsorption isotherms of PSP to POS@PANI-EB and POS@PANI-ES, yielding the thermodynamic parameters of adsorption. The adsorption capacities of PSP on POS@PANI-EB and POS@PANI-ES were 37.8 and 71.5 μmol g-1, respectively. The adsorption of PSP remained above 80% at moderate salt concentrations of around 0.1 mol L-1; however, higher concentrations of NaCl and CaCl2 in PSP solutions significantly reduced the adsorption on POS@PANI-ES.

Effect of NaCl, CaCl2, and sucrose on the rheological properties of agar from Gracilaria in Vietnam

Agar is a polysaccharide extracted mainly from Gracilaria. Agar is widely used in the food industry as a viscous agent, thickness, emulsifier or food stabiliser. The presence of NaCl, CaCl2 or sucrose influences in sol-gel transition, viscosity of the agar solution or gel strength of the agar. Agar forms a gel at high concentration or lower one if there is the presence of NaCl, CaCl2 or sucrose. Gelling temperature (Tg) of agar solution at 0.2 wt% increasing at 36, 36 or 38°C upon addition of 300 mM NaCl, 100 mM CaCl2, or 30% sucrose, respectively. The viscosity of the 0.2% agar solution increased insignificantly when the ionic strength was below 100 mM, but increased sharply above 100 mM. The gel strength increases with added NaCl, CaCl2 up to 100 mM, 30 mM, respectively; then they drop slightly at higher concentrations of NaCl, CaCl2. Meanwhile, the viscosity of agar solution only increases at sucrose concentrations above 10%. Gel strength increased with increasing sucrose concentration, being 1.2 to 1.8 times higher if 30% sucrose was added.

Enhancing simultaneous saccharification and co-fermentation of corncob by Kluyveromyces marxianus through overexpression of putative transcription regulator

Overexpression of a gene with unknown function in Kluyveromyces marxianus markedly improved tolerance to lignocellulosic biomass-derived inhibitors. This overexpression also enhanced tolerance to elevated temperatures, ethanol, and high concentrations of NaCl and glucose. Inhibitor degradation and transcriptome analyses related this K. marxianusMultiple Stress Resistance (KmMSR) gene to the robustness of yeast cells. Nuclear localization and DNA-binding domain analyses indicate that KmMsr is a putative transcriptional regulator. Overexpression of a mutant protein with deletion in the flexible region between amino acids 100 and 150 further enhanced tolerance to multiple inhibitors during fermentation, with ethanol production and productivity increasing by 36.31 % and 80.22 %, respectively. In simultaneous saccharification co-fermentation of corncob without detoxification, expression of KmMSR with the deleted flexible region improved ethanol production by 5-fold at 42 °C and 2-fold at 37 °C. Overexpression of the KmMSR mutant provides a strategy for constructing robust lignocellulosic biomass using strains.

Electrocatalytic reduction of nitrate to ammonia by Pd/In modified Nickel foam electrode in aqueous solution

Nitrate pollution in surface water and ground water has drawn wide attention, which has brought challenges to human health and natural ecology. Electroreduction of nitrate to NH3 in waste water was a way to turn waste into wealth, which has attracted interest of many researchers. Using Nickel foam as substrate, we prepared Pd/In bimetallic electrode (NF–Pd/In) according to a two-step electrodeposition method. There are many irregularly shaped particles in the size range of 10 nm–100 nm accumulated on the surface of prepared NF–Pd/In electrode, which could supply high specific area and more active sites for nitrate electroreduction. FESEM-EDS, XRD and XPS analysis confirmed the uniform distribution of Pd and In on the surface of prepared NF–Pd/In electrode, with a mass ratio of 4.5/1. Above 96% of 100 mg/L NO3−-N was removed and 95% of NH3 selectivity was reached after 5 h of reaction under −1.6 V vs. Ag/AgCl sat. KCl when using 0.05 mol/L of Na2SO4 as electrolyte. High concentration of NaCl (0.05 mol/L) in the test solution dramatically decreased the NH3 selectivity because the produced NH3 could be further oxidized to N2 by the formed HClO from Cl−. EIS tests indicated that the prepared NF–Pd/In electrode showed much lower electrode resistance than NF due to the adsorptive property and electrocatalytic ability for nitrate removal. Density functional theory (DFT) calculations indicated that the presence of In could promote the conversion of NO3− to *NO3 during the process of nitrate electroreduction to NH3. Circulating tests demonstrated the stability of prepared NF–Pd/In electrode.

Salicylic Acid Alleviates the Adverse of Salinity Stress in Fenugreek (Trigonella foenum-graecum)

Aims: To discover the resistance of the Yemeni genotype of fenugreek to salt stress and the impact of salicylic acid on alleviating salt stress. Study Design: The experimental design adopted a completely randomized block design (RCBD), with pots filled with a 1:2 mixture of sand and soil serving as the experimental units. Place and Duration of Study: in a mini greenhouse covered with white polyethylene plastic sheet at Taiz University during the spring season 2021. The average temperature ranged from 32 ℃ during the day to 29 ℃ at night. chemical analyses were performed at the pharmaceutical laboratory in Al-Saeed University. Methodology: The fenugreek genotype was subjected to varying salinity levels (0, 50, 100, 150, and 200 mM) and the impact of salicylic acid (at concentrations of 0, 0.1, and 0.5 mg/l) in alleviating salt stress effects was examined at two time points: 15 and 30 days after 2 weeks of germination. Results: Increasing salinity significantly reduced shoot and root length and exhibited slight fluctuations influenced by salinity levels above 100 mM. Salicylic acid (SA) significantly reduced shoot length but had no effect on root length. Salinity had no appreciable effect on shoot dry matter (SDM%), while the application of SA significantly decreased it. Root dry matter percentage (RDM%) showed a notable and sharp increase with salinity. However, no appreciable changes in RDM% were observed in response to the SA application. In response to salinity, the ratio of SDM% to RDM% in treated plants decreased sharply, with the lowest ratio achieved when 0.1 SA was used for treatment. There were no significant modifications observed in the amounts of photosynthetic pigments in fenugreek leaves, including chl a, chl b and total chl. Nevertheless, using high concentration of Nacl led to a signifcantly reduced in the carotenoids and the chl. b. The protein content of fenugreek plants treated with salt was much higher than that of control plants. Also, protein levels increased with SA treatment across all NaCl concentration. Proline levels sharply increased with rising salinity, reaching a peak in approximately 22.28 ug/g DW. Application of 0.1 SA led to the highest proline level in comparison to other treatments, which was the highest level of Nacl in the second measurement time. Proline levels in plants treated with 200 Nacl and 0.1 SA were the highest, averaging roughly recorded 49.95 ug/g DW. APX significantly affected on fenugreek plants, the highest APX content was found in plants treated with 50 mM NaCl, the application of 0.1 SA produced the highest level of APX (0.373nm/g protein/minuet) in fenugreek. Catalase (CA) levels significantly decreased, but SA application did not affect CA levels. The data obtained may help in determining fenugreek cultivation areas and in managing breeding programs.

Tri-frequency simultaneous ultrasound pickling for the acceleration of the NaCl content and quality improvement of pork (longissimus dorsi).

The pickling process with NaCl is an essential step for pork preservation. This study aimed to investigate the effect of different ultrasonic intensities of tri-frequency simultaneous ultrasound (TSIU) pickling on the NaCl content and quality of pork (longissimus dorsi). After 30 min pickling, the NaCl content, moisture content, pickling yield, cooking loss, textural properties, color, pH, moisture migration and distribution as well as microstructure of pork were assessed. Results showed that among all the ultrasonic treatment intensities (85-150 W L-1), the NaCl content of the sample pickled by an intensity of 101.3 W L-1 was higher than that of other intensities. TSIU 101.3 W L-1 showed 59.95% higher NaCl content than the control sample. In addition, the sample treated with TSIU of 101.3 W L-1 had higher pickling yield and moisture content, better textural properties of pork (including hardness and chewiness), and less cooking loss. The results of the low-field nuclear magnetic resonance showed that, compared with the control group, the relaxation time T21 of the ultrasound-assisted pickling samples increased, while the proportion of T22 (A22) reduction ranged from 175.0% to 379.9%. The microstructure designated that the ultrasonic treatment could facilitate changes in meat texture. Ultrasound marination of different intensities promoted the diffusion of NaCl and affected the quality of pork tenderloins. The TSIU at 101.3 W L-1 could better accelerate NaCl transport and homogeneous distribution on meat, thereby improving the sample quality. © 2024 Society of Chemical Industry.

“Halotolerant fungi secreting phytohormones and volatile organic compounds enhance growth and mineral content in finger millet under salinity stress”

Soil salinity is one of the major environmental stresses that significantly hampers crop yield worldwide. This study assessed the effectiveness of the rhizospheric fungus, Aspergillus sojae JUSPF-101, in enhancing the tolerance of finger millet seedlings to NaCl stress. The research also examined the role of JUSPF-101 in producing phytohormones and volatile organic compounds. The impact of A. sojae was evaluated on both primed and unprimed finger millet seedlings (using Petri dish and pipette tip bioassay methods) under NaCl stress conditions. A study was conducted in a greenhouse to confirm the growth characteristics and mineral composition of finger millet seedlings, both with and without inoculation of A. sojae JUSPF-101. These seedlings were exposed to varying concentrations of NaCl (0 and 400 mM).The current research demonstrated that A. sojae could withstand high concentrations of NaCl (up to 1200 mM) and high temperatures (45 °C). Using LC-MS/MS, fifteen phytohormones were identified in A. sojae grown under NaCl concentrations of 0 and 400 mM. These include IAA, SA, GA4, epibrasinolide, the trans isomer of zeatin, and cis-jasmone. The GC–MS analysis detected seventy-seven VOCs, with the major compound being 1-(4-Amino-furazan-3-yl)-5-propyl-1H-[1,2,3]triazole-4-carboxylic acid ethyl ester (8.7%). Moreover, finger millet seedlings that were not treated displayed a significant decrease in RWC and biochemical parameters such as proline, phenols, and flavonoids (p < 0.05), while there was an increase in MDA and H2O2 content. However, using A. sojae effectively alleviated the stress caused by NaCl and led to improvements in RWC, growth, and biochemical parameters.The application of A. sojae under 400 mM NaCl treatment, significantly increased morphological (shoot and root length) and biochemical parameters such as proline (1.67-fold), phenols (2.15-fold), and flavonoids (2.04-fold) while MDA (1.2-fold), and H2O2 (1.25-fold) decreased as compared to unprimed seedlings under NaCl stress. In a greenhouse environment, seedlings treated with A. sojae showed improved growth parameters and lower Na+/K+ and Na+/Ca2+ ratios. These findings suggest that applying A. sojae (JUSPF-101) could be an effective strategy for reducing NaCl stress in finger millet, contributing to sustainable food security.

Study of the Formation of Hydrates with NaCl, Methanol Additive, and Quartz Sand Particles

During deepwater drilling, testing, production, or hydrate mining, the circulating medium in the wellbore may contain solid particles, such as rock chips and sand, in addition to drilling fluids, gas, and water. In the high-pressure, low-temperature conditions of deep water, gas intrusion can easily combine with free water in the drilling fluid to form hydrates, increasing the drilling risk. Therefore, understanding the formation patterns of hydrates in drilling fluids is of significant importance for the prevention and control of hydrates. This study utilized a small-scale high-pressure reactor to investigate the impact of the stirring rate, NaCl, and methanol additives, as well as the sand content on the hydrate formation process and gas consumption. The results indicate that the hydrate formation process can be divided into an induction stage, a rapid formation stage, and a slow formation stage. The induction stage and rapid formation stage durations are significantly reduced under stirring conditions. In NaCl and methanol solutions, hydrate formation is inhibited, with the induction stage duration increasing with higher concentrations of NaCl and methanol. There was no apparent rapid formation stage observed. The final gas consumption decreases substantially with increasing concentrations of NaCl and methanol, reaching no significant hydrate formation at a 20% concentration. The sand content has a significant impact on the slow formation stage, with the final gas consumption increasing within a certain range (in this work, at a sand content of 20%), and being notably higher than in the pure water system under the same conditions.

Effects of NaCl application on cesium concentration, number, and size of epidermal bladder cells in quinoa plants

Quinoa (Chenopodium quinoa Willd.) plants possess epidermal bladder cells (EBCs) on the leaf surface that accumulate excess sodium (Na+). However, whether excess cesium (Cs+) is transported from the leaf to the EBCs has not been elucidated in quinoa plants. In this study, the Cs+ concentration of EBCs and leaves of quinoa plants grown in soil treated with high concentrations of NaCl was investigated via pot experiments. Three different treatments were performed: 9.75 g plot, and 19.50 g plot, and a control (with no added NaCl). In 9.75 g plot and 19.50 g plot, 9.75 g and 19.5 g of NaCl were applied to the soil, respectively. And 0.10 g of CsCl were applied to all pots. We observed that Na+ concentration in EBCs and leaves with and without EBCs increased with increasing NaCl concentration at the vegetative and flowering stages; Na+ concentration was lower in the EBCs than in both types of leaves at both growth stages. Cs+ concentration in EBCs and both types of leaves increased with increasing NaCl concentration; Cs+ concentration was higher in EBCs than in both types of leaves at both growth stages. However, NaCl application did not affect the number of EBCs at both growth stages, but the number of EBCs in older leaves was lower than that in younger leaves at both growth stages. Moreover, EBC diameter increased with NaCl application at both growth stages; the EBCs of younger leaves (1st leaf) were larger than those of older leaves (5th leaf) at both growth stages. Therefore, NaCl increased the Cs+-accumulation capacity of quinoa plants by increasing the size of the EBCs.

Lable-free aptamer portable colorimetric smartphone for gliadin detection in food.

For individuals with celiac disease (CD), the current clinical therapy option available is a lifelong gluten-free diet. Therefore, it is essential to swiftly and efficiently detect gluten in foods. A colorimetric sensor has been developed, which operates by regulating the aggregation and dispersion state of AuNPs induced by high concentration NaCl through the specific binding of gliadin and aptamer, thereby achieving rapid detection of gliadin in flour. It is found that the sensor exhibits good linearity in the concentration range of 0.67-10μM and the LOD (3σ/S) is 12nM. And it can accurately distinguish various types of free-gliadin samples, with a spiked recovery rate of 85%-122.3%. To make the detection process more convenient, the colorimetric results of the biosensor were translated into RGB color-gamut parameters by a smartphone color-picking program for further analysis. Gliadin can still be accurately quantified with the established smartphone platform, and a correlation coefficient of 0.988 was found. The proposed portable smartphone aptamer colorimetric sensing device has achieved satisfactory results in the rapid detection of gliadin in food.

Exploring rhizobacteria of wild sugarcane (Saccharum spontaneum L.) and their plant growth promoting potential

In this study, the rhizospheric soil of wild sugarcane from three different salt-affected soils of the eastern Indo-Gangetic Plains was sampled. Rhizospheric bacteria from S. spontaneum were isolated and they were characterized for growth-promoting traits with molecular identification. A total of 49 isolates were isolated from three S. spontaneum rhizosphere soils from different places. These isolates were shown to have differential tolerance to NaCl concentrations up to 2000 mM. Owing to their host habitat and poor nutrient availability, these bacteria were found to have excellent tolerance to high NaCl concentrations along with having multiple plant growth traits. Apart from salt tolerance, these isolates were screened for EPS production, phosphate solubilization, zinc solubilization, siderophore production and ammonia production and based on multiple plant growth-promoting traits, twenty isolates were taken for molecular identification and further in vivo screening. These twenty S. spontaneum rhizospheric microbes belonged to the classes Gammaproteobacteria, Firmicutes (Bacilli) and Actinomycetia, representing six genera and 15 species. In vivo growth promotion studies indicated that some of these isolates could improve germination and growth in rice seedlings. The results of this study signify the possibility of utilizing wild crop microbiomes to nurture cultivated crops under adverse growing conditions.

Efficient In Vitro Platform for Multiplication, Acclimatization, and Deliver of High-NaCl-Tolerant Clones of the Halophyte Arthrocaulon macrostachyum

Halophytes are species able to grow and complete their life cycle under NaCl concentrations above 0.2 M. In a context of growing population and uncertain agricultural food sustainability, there is an interest on halophytes as potential source of food and fodder. However, scarce research has addressed in vitro propagation of halophytes as a tool for study, conservation, and propagation of elite germplasm. In this study, an efficient method for micropropagation of the succulent and salt accumulator halophyte Arthrocaulon macrostachyum has been established for the first time, using shoot tips from in vitro-germinated plant material. During shoot multiplication stage, superior genotypes were selected from explants grown in high strength and NaCl content medium and subsequently rooted and acclimatized to ex vitro conditions. A comprehensive characterization including determination of oxidative stress, photosynthesis performance, and mineral nutrient contents was done. This research gains insight into the physiological and biochemical characterization of halophytes during micropropagation and provides a solid platform for the production of elite A. macrostachyum germplasm for ulterior uses.

A model to reduce tyrosine crystallization in Chinese fermented soybean curd by adjusting NaCl, ethanol and temperature during fermentation

Abstract Objectives White spots, mainly consisting of tyrosine, refer to small white particles that exist on the surface of mature Chinese fermented soybean curd or in the fermentation broth and have affected the appearance of Chinese fermented soybean curd. Materials and Methods The study determined the composition of the white spots throughout mass spectrometry and high-performance liquid chromatography and investigated the relationship between tyrosine content, amino acid nitrogen content, depth of the proteolysis index and protease activity to interpret the mechanism of white spot formation during fermentation. Results In this study, the results confirm that tyrosine accounts for 78.22% of the white spots. Excessive tyrosine content can promote the formation of white spots during fermentation. Free tyrosine content, amino acid nitrogen content, depth of the proteolysis index and protease activity during the fermentation process increased during fermentation. Correlation analysis results show that free tyrosine content was positively correlated with amino acid nitrogen content, depth of the proteolysis index and protease activity, which showed that the production of tyrosine is related to the degree of proteolysis. Solubility studies show that high concentrations of NaCl and ethanol affect the production of tyrosine and reduce its solubility, while the increase in temperature increases the solubility of tyrosine. Taking NaCl, ethanol and temperature as influencing factors, a mathematical model of tyrosine solubility was established. Conclusion This study lays the groundwork for understanding the mechanism of white spot formation during Chinese fermented soybean curd fermentation and provides solutions for controlling white spot formation.

Development and Regulation of the Extreme Biofilm Formation of Deinococcus radiodurans R1 under Extreme Environmental Conditions.

To grow in various harsh environments, extremophiles have developed extraordinary strategies such as biofilm formation, which is an extremely complex and progressive process. However, the genetic elements and exact mechanisms underlying extreme biofilm formation remain enigmatic. Here, we characterized the biofilm-forming ability of Deinococcus radiodurans in vitro under extreme environmental conditions and found that extremely high concentrations of NaCl or sorbitol could induce biofilm formation. Meantime, the survival ability of biofilm cells was superior to that of planktonic cells in different extreme conditions, such as hydrogen peroxide stress, sorbitol stress, and high UV radiation. Transcriptome profiles of D. radiodurans in four different biofilm development stages further revealed that only 13 matched genes, which are involved in environmental information processing, carbohydrate metabolism, or stress responses, share sequence homology with genes related to the biofilm formation of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Overall, 64% of the differentially expressed genes are functionally unknown, indicating the specificity of the regulatory network of D. radiodurans. The mutation of the drRRA gene encoding a response regulator strongly impaired biofilm formation ability, implying that DrRRA is an essential component of the biofilm formation of D. radiodurans. Furthermore, transcripts from both the wild type and the drRRA mutant were compared, showing that the expression of drBON1 (Deinococcus radioduransBON domain-containing protein 1) significantly decreased in the drRRA mutant during biofilm development. Further analysis revealed that the drBON1 mutant lacked the ability to form biofilm and DrRRA, and as a facilitator of biofilm formation, could directly stimulate the transcription of the biofilm-related gene drBON1. Overall, our work highlights a molecular mechanism mediated by the response regulator DrRRA for controlling extreme biofilm formation and thus provides guidance for future studies to investigate novel mechanisms that are used by D. radiodurans to adapt to extreme environments.

Formation of lipid corona on Ag nanoparticles and its impact on Ag+ ion dissolution and aggregation of Ag nanoparticles against external stimuli

The application of lipid coated nanoparticles has been expanding in nanoscience over the past few years. Lipid corona formation is one of the novel ways for the lipid conjugation around the nanoparticles. Although several properties of nanoparticles and lipids are well reported in literature in last few years, the dependency of lipid corona formation on metallic core and surface ligands is poorly understood. The aggregation, surface oxidation and metal ions dissolution of nanoparticles limit their usefulness in various applications. Besides all the reported methods to overcome all of these limitations, lipid corona could be an alternative, feasible, and more efficient method. In the current manuscript, we investigate the interaction of aromatic amino acids (tyrosine and tryptophan) functionalized silver nanoparticles (Ag-Tyr and Ag-Trp NPs) with different surface charged and phase states lipid vesicles and compare them with the reported amino acid functionalized gold nanoparticles (Au-AA NPs). The effectiveness of different zwitterionic and positively charged lipid coated Ag-Tyr and Ag-Trp NPs to prevent the aggregation and Ag+ ion dissolution of Ag NPs against different external stimuli (acidic pH, high NaCl concentration, and freeze-thaw cycles) are investigated. Our results reveal that surface ligands around the NPs play crucial role for lipid corona formation irrespective of the metallic core of NPs. Although all the lipid coated Ag NPs exhibit greater stability against external stimuli than native Ag NPs, zwitterionic lipid coated Ag NPs is better choice than positively charged lipid coated Ag NPs. This study on lipid corona and its stability will help the nanoresearcher to choose the suitable lipid for lipid corona formation.

Enhancing corrosion and tribology performance of stainless steel with DLC coatings: Effects of doping and multilayered structures

The increasing demand for energy production has expanded oil and gas extraction, particularly in harsh exploration sites with highly corrosive media. In the Brazil's pre-salt layer, rich in oil reserves, high NaCl content and CO2 presence may induce sweet corrosion. Corrosion resistant alloys are often used for better performance, and among them, austenitic stainless steels (SS) offer good balance of cost and properties. However, pre-salt acidic and salty environment may induce localized corrosion, making protective coatings a viable option to prolong the lifespan of components exposed to these environments. Diamond-like carbon (DLC) coatings are a great alternative, as besides being chemically stable, they improve mechanical properties of the coated material, such as higher hardness and wear resistance and lower friction coefficient. Therefore, the performance of different types of DLC on the anti-corrosion protection of SS was evaluated. Four DLC types were tested: a hydrogenated amorphous DLC; a multilayered film (DLC-M); and films with fluorine (DLC-F) and silicon (DLC-S). The films showed chemical and structural differences, evidenced by Raman, SEM/EDS and XPS analysis. Their tribological performances were evaluated through scuffing resistance tests; the base DLC showed the highest resistance, followed by DLC-F and DLC-M. DLC-S films didn't exhibit satisfactory tribological performance. For corrosion characterization, potentiodynamic polarization tests were conducted in NaCl and CO2-saturated NaCl solutions. In the NaCl tests, DLC films exhibited impressive anti-corrosion properties, with DLC-F delivering the highest performance, followed by DLC-M, DLC-S, and base DLC. 316 L SS showed high corrosion susceptibility in the CO2-saturated solution, but the coatings also improved corrosion resistance in this setting. The DLC, DLC-S and DLC-M showed similar Ecorr and jcorr values, while DLC-F demonstrated superior corrosion resistance with higher Ecorr and lower jcorr values.

Laminated chitosan/graphene nanoplatelets aerogel for 3D interfacial solar desalination with harnessing wind energy

Interfacial solar steam generation (ISSG) is a novel approach to freshwater generation. In practical utilization of new ISSG technology, achieving high evaporation rate is a crucial step. A three-dimensional (3D) solar absorber can increase the exposed surface area and enhance the escape of water molecules to the surrounding environment. However, vigorous evaporation induces to dry out the evaporator quickly, leading to damage its structure or decreased efficiency. In this context, a transversely laminated aerogel-based 3D evaporator is proposed. For this, chitosan/graphene nanoplatelets (CG) are incorporated to create laminated CG (LCG) aerogels having two different densities in a single structure. The results demonstrate that LCG aerogels exhibit rapid water-rise ability and excellent solar absorption characteristics. The laminated structure enhances mechanical strength and maintains balanced water and ion gradients sustainably, inducing a wettable and evaporation-enhanced condition. With these advantages, the evaporation rate of LCG aerogels with aspect ratio (AR) of 7 achieves 2.17 kg m−2h−1. In addition, evaporation experiments were conducted by applying precisely-controlled wind in a wind tunnel to the 3D evaporator. At a wind speed of 6 m s−1, the proposed evaporator achieves a maximum evaporation rate of 5.98 kg m−2h−1. Aerogel with a single density is better suited for situations where only solar radiation is present, while the LCG aerogel, which can utilize the features of two densities at the same time, is more effective in windy conditions. The evaporation efficiency is over 73 % for seawater and 20 wt% high-concentration NaCl solution, showing excellent durability with salt-resistance. The proposed aerogel-based evaporators would be utilized as a sustainable seawater desalination technology for environmentally friendly freshwater production.

Effects and mechanisms of different κ-carrageenan incorporation forms and ionic strength on the physicochemical and gelling properties of myofibrillar protein

The present work was aimed to investigate the effects of incorporating κ-carrageenan into myofibrillar protein (MP) as a dry powder (CP) or water suspension (CW) and the ionic strength (0.3 or 0.6 M sodium chloride (NaCl)) on MP physicochemical and gelling properties. The results indicated that incorporation of either CP or CW significantly increased turbidity, surface hydrophobicity, particle size and rheological behaviour of MP. In contrast, the protein solubility and fluorescence intensity of MP decreased when added with each form of κ-carrageenan (P < 0.05). These observed effects improved MP's gelling properties and produced a more compact and homogenous gel network after heating treatment. Moreover, the addition of CW rendered higher gel strength, water holding capacity and intermolecular interactions, such as ionic, hydrogen and disulphide bonds and hydrophobic interactions in MP gel compared with those added with CP, especially for 0.3 M NaCl (P < 0.05). Furthermore, addition of CW significantly decreased the α-helix content of MP gels (P < 0.05), which mainly contributing to the transformation from a random structure to an organised configuration. In addition, a higher NaCl concentration (0.6 M) enhanced the gelling properties of MP gels compared with 0.3 M NaCl concentration in the presence of each form of κ-carrageenan. Therefore, our present study indicated that incorporation form of κ-carrageenan and ionic strength have distinctive effects on regulating physicochemical characteristics and improves gelling properties of MP.