Optimal Concentration Research Articles

Thiol-ene Click Chemistry Synthesis of L-Cysteine-Grafted Graphene Oxide As a New Corrosion Inhibitor for Q235 Steel in Acidic Environment.

l-cysteine, as an eco-friendly and nontoxic corrosion inhibitor, was directly covalently linked to the carbon/carbon double bonds of the GO flakes by a thiol-ene click reaction to avoid decreasing the number of hydrophilic oxygen-containing polar functionalities. The corrosion inhibition performances of Cys-GO toward Q235 steel (QS) in diluted hydrochloric acid were studied by electrochemical methods. The corrosion was a charge transfer-controlled process, and Cys-GO manifested as a mixed-type corrosion inhibitor. The corrosion inhibition efficiency (η) for QS showed a first-increase-and-then-decrease trend with increasing Cys-GO concentrations. The optimum concentration of Cys-GO was 15 mg L-1, and the according η value was up to 90%. The Cys-GO adsorbed on the QS surface to form a protective barrier was responsible for the efficient corrosion inhibition. Langmuir adsorption isotherm model was fitted well with the experiment data, indicating a monolayer adsorption. Furthermore, the coordinate covalent bonds, π-back-donation effect, and electrostatic attraction were responsible for the Cys-GO adsorption on the QS surface.

Amelioration of protective organic layer using acenaphthene-based inhibitor responsible for excellent anti-corrosion performance: Experimental and computational perspectives

Despite the engineering promise offered by the co-existence of organic substances in protecting vulnerable metallic materials from corrosive environments, the interaction and formation mechanisms that induce the development of new materials with improved structural properties remain less understood. This study investigated the corrosion inhibitory properties of two acenaphthene derivatives, acenaphthylene-1,2‑dione (ACP) and 1,2-dihydroacenaphthylen-1-ol (DCP), as inhibitors for N80 steel in a 15 % HCl solution. The anticorrosive effectiveness of ACP and DCP compounds was evaluated through multiple research methods, including weight loss analysis, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and surface characterization using scanning electron microscopy (SEM). The experimental findings demonstrate that ACP exhibits superior inhibition performance compared to DCP, with an inhibition efficiency of 93.54 % for ACP and 73.12 % for DCP at an optimum concentration of 5 × 10–3 M. EIS data show that the charge transfer resistance increases with higher concentrations of both compounds. PDP results indicate that ACP and DCP act as mixed-type inhibitors without altering the corrosion mechanism. The kinetic parameters of corrosion adsorption follow the Langmuir isotherm, highlighting a competition between physical and chemical interactions. To investigate how the geometric structures resulting from functional groups influence their interaction with the metal surface, theoretical calculations employing density functional theory (DFT), molecular dynamics (MD), and density-functional tight-binding (DFTB) were conducted. These calculations were aimed at gaining insights into the adsorption behavior of ACP and DCP on the metal surface and their interfacial mechanism. The calculations demonstrate that the molecule possessing twin donor atoms along with p-type orbitals of aromatic rings significantly influenced the formation of a protective film with a uniform distribution. This configuration exhibited superior corrosion performance compared to a molecule containing only one hydroxyl group (—OH). Theoretical calculations further suggest that ACP exhibits stronger adsorption ability, with the two oxygen atoms identified as the most reactive sites, indicating their tendency to donate electrons to the iron surface. The robust resonance-stabilized structure of ACP enhances the stability of the molecules, facilitating its interaction and adsorption onto the metal surface compared to the DCP inhibitor. Overall, the superior inhibition performance of ACP is attributed to the close bonding of twin donor fragments within the ACP molecule, forming a more compact adsorbed inhibitor film on the steel surface.

A method for screening salt stress tolerance in Indian mustard (Brassica juncea) (L.) Czern & Coss at seedling stage

Fifty-nine diverse Brassica juncea (Indian mustard) genotypes were used to find an effective screening method to identify salt tolerance at the germination and seedling stages. Salinity stress limits crop productivity and is difficult to simulate on farms, hindering parental selection for hybridization programmes and the development of tolerant cultivars. To estimate an optimum salt concentration for screening, seeds of 15 genotypes were selected randomly and grown in vitro at 0 mM/L, 75 mM/L, 150 mM/L, 225 mM/L, and 300 mM/L concentrations of NaCl in 2 replications in a complete randomized design. Various morphological parameters, viz., length of seedling, root and shoot length, fresh weight, and dry weight, were observed to determine a single concentration using the Salt Injury Index. Then, this optimum concentration (225 mM/L) was used to assess the salt tolerance of all the 59 genotypes in 4 replications while observing the same morphological parameters. With the help of Mean Membership Function Value evaluation criteria, the genotypes were categorized into 5 grades: 4 highly salt-tolerant (HST), 6 salt-tolerant (ST), 19 moderately salt-tolerant (MST), 21 salt-sensitive (SS), and 9 highly salt-sensitive (HSS). Seedling fresh weight (SFW) at 225 mM/L was found to be an ideal trait, which demonstrates the extent to which B. juncea genotypes respond to saline conditions. This is the first report that establishes a highly efficient and reliable method for evaluating the salinity tolerance of Indian mustard at the seedling stage and will facilitate breeders in the development of salt-tolerant cultivars.

High-efficiency removal of diclofenac sodium (DS) drug using chitosan-grafted-poly(acrylic acid-co-N-isopropylacrylamide)/kaolin clay hydrogel composite

ABSTRACT The current study mainly deals with the adsorptive removal of the diclofenac sodium (DS) drug from aqueous solution by the use of the kaolin-CS-g-poly(AA-co-NIPAM) composite. The synthesised composite was characterised by Fourier Transform infrared (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Transmission electron microscopy (TEM), energy dispersive X-Ray spectroscopy (EDS), atomic force microscopy (AFM), swelling % ratio and point of zero charge ( p H PZC ). The pHpzc of the composite was determined to be 4. The maximum adsorption capacity of 18.51 mg/g observed at the optimised conditions, including 0.1 g of kaolin clay dose, at neutral pH using composite dose of 0.06 g for 90 min. The optimum drug concentration was 500 mg/l for temperature of 30°C. Effect of the ionic strength on the adsorption capacity of the composite and its mechanism for DS drug removal has also been investigated. The process of drug adsorption on the prepared composite was chemical and data fits well to the pseudo second order and Langmuir model. Overall, the process was spontaneous and endothermic in nature.

Does using a higher dialysate sodium concentration result in lower sodium losses with dialysis treatments?

IntroductionMany dialysis centres prescribe a uniform dialysate sodium (DialNa) concentration, but as there is no consensus on the choice of a universal DialNa, we wished to determine dialysate sodium balance comparing DialNa of 140 and < 140 mEq/L.MethodsWaste dialysate was continuously collected during sessions and thoroughly mixed, and sodium was measured in both the waste and fresh dialysate. Sodium removal was calculated as the difference in concentrations, dialysate flow rate, session time and ultrafiltration.ResultsDialysate sodium balance was measured during 139 dialysis treatments (34 DialNa 140 versus 105 DialNa < 140, median 136 mEq/L), in 111 patients, 63% male, mean age 64.0 ± 16.2 years and 33.3% diabetic. There was no difference using the higher DialNa [net loss median 482 (238–573) versus 312 (124–599) mEq], ultrafiltration losses [226 (131–280) versus 204 (125–290)mEq] and non-ultrafiltration losses [217 (0–384) versus 173 (−90 to 350)mEq]. We also compared haemodiafiltration and haemodialysis (118 versus 23 sessions), and there were no differences in net loss [311 (91–608) versus 381 (167–597)], ultrafiltration [212 (127–290) versus 169 (110–258)mEq] and non-ultrafiltration losses [180 (−51 to 386) versus 192 (−74 to 387)mEq].ConclusionsAlthough most dialysis centres prescribe a universal dialysate sodium concentration, there is no consensus on the optimum universal concentration. We found no difference in net dialysate sodium balance when comparing patients dialysing with a dialysate sodium concentration of 140 or < 140 mEq/L. Similarly, we found no differences in dialysate sodium balance between haemodiafiltration and haemodialysis sessions.

Salt ions improve soybean protein isolate/curdlan complex fat substitutes: Effect of molecular interactions on freeze-thaw stability

Although emulsion gels show significant potential as fat substitutes, they are vulnerable to degreasing, delamination, and other undesirable processes during freezing, storage, and thawing, leading to commercial value loss in terms of juiciness, flavor, and texture. This study investigated the gel strength and freeze-thaw stability of soybean protein isolate (SPI)/curdlan (CL) composite emulsion gels after adding sodium chloride (NaCl). Analysis revealed that adding low salt ion concentrations promoted the hardness and water-holding capacity (WHC) of fat substitutes, while high levels displayed an inhibitory effect. With 40 mM NaCl as the optimum concentration, the hardness increased from 259.33 g (0 mM) to 418.67 g, the WHC increased from 90.59 % to 93.18 %, exhibiting good freeze-thaw stability. Confocal laser scanning microscopy (CLSM) and particle size distribution were used to examine the impact of salt ion concentrations on protein particle aggregation and the damaging effect of freezing and thawing on the proteoglycan complex network structure. Fourier-transform infrared spectroscopy (FTIR) and protein solubility evaluation indicated that the composite gel network structure consisted of covalent contacts between the proteoglycan molecules and hydrogen bonds, playing a predominant role in non-covalent interaction. This study showed that the salt ion concentration in the emulsion gel affected its molecular interactions.

Green Synthesis of Silver Nanoparticles Using Aqueous Fruit Peel Extract of Citrus aurantifolia: Optimization, Its Characterization and Stability Test

In this present study, silver nanoparticles were synthesized by green biological synthesis method using plant extract from fruit peel of Citrus aurantifolia as reducing agents. All the parameters in the synthesis of silver nanoparticles (AgNPs) were optimized to achieve a better yield, controlled size and stability of the particles. The biosynthesis of silver nanoparticles was monitored via UV-vis spectrophotometer and stability test was done. The resulting UV-Vis spectra of synthesized AgNPs from C. aurantifoliafruit peel extract (CAFPE) showed standard surface plasmon resonance band at 420 nm which indicated the presence of AgNPs. The optimum result was obtained with an optimum concentration at 4 mM AgNO3, leaving in a dark room temperature for 24 h and using a concentration 1:3 ratio (extract: silver nitrate). Moreover, the stability of the CAFPE-AgNPs was also observed after 30 days of synthesis and even up to 10 months, indicating optimization plays major role towards the stability fate of nanoparticles. The FTIR analysis showed possible functional groups of biomolecules that play roles in the bioreduction and capping of silver nanoparticles. In addition, it is believed that these parameters are highly suitable for bulk production of single spherical AgNPs with diameter 29.6- 45.2 nm confirmed via FESEM. Thus, the obtained results clearly suggest that optimization of silver nanoparticles may have important role in attaining a better yield and stability of metal nanoparticles, refraining back to its original structure or particles.

Effects of hydroxytyrosol on post-thaw quality of rooster sperm.

Semen cryopreservation is one of the most important reproduction techniques in the livestock and poultry industry. Cryopreservation induces cold stress, generating reactive oxygen species (ROS) and oxidative stress causing structural and biochemical damages in sperm. In this study, we evaluated the effects of the hydroxytyrosol (HT), as an antioxidant, at the concentrations of 0, 25, 50, and 100 μg/mL on post-thaw semen quality metrics in rooster. Semen samples were collected twice a week from 10 roosters (29 weeks), processed and frozen according to experimental groups. Different quality parameters, including total motility, progressive motility, viability, morphology, membrane integrity, and malondialdehyde were measured after thawing. Results showed that 25 and 50 μg/mL of HT produced the highest percentage of total motility (51.01 ± 2.19 and 50.15 ± 2.19, respectively) and progressive motility (35.74 ± 1.34 and 35.15 ± 1.34, respectively), membrane integrity (48.00 ± 2.18 and 46.75 ± 2.18, respectively) as well as viability (53.00 ± 2.17 and 52.50 ± 2.17, respectively) compared with the other groups (p < .05). The group with 25 μg/mL of HT showed the lowest significant (p < .05) MDA concentration (1.81 ± 0.25). Our results showed that the effect of HT was not dose-dependent and optimum concentration of HT could improve functional parameters of rooster sperm after freezing-thawing. These findings suggest that HT may have protective effects on the rooster sperm during the freezing-thawing process.

Recovery of Propionic Acid from Aqueous Phase using Alamine 336 in 1 - Octanol by Reactive Extraction

The by-products of carboxylic acids are useful in chemical industry, pharmaceutical industry, preservations, drug delivery towards a more economical energy efficient technology. Physical and chemical equilibria results are presented as equilibrium distribution, distribution co -efficient, extraction efficiency, loading ratio and volume percentage by varying concentrations. The distribution of propionic acid between aqueous phase and organic phase reaches equilibrium over a concentration range of 0.009 kmol/m3 – 0.055 kmol/m3 . The optimum TOA concentration is found to be 40% at which KD value for 1 - octanol is 16.7. The modified separation increases with decrease in TOA &amp; acid concentration and alamine loading with acid Z decreases with increase in alamine concentration in 1 – octanol. Optimum extraction efficiency is 43.82% for a conc. of 40% TOA at 0.2 kmol/m3.

Preparation and Evaluation of Metronidazole Tablets Produced with Different Binders Using Wet Granulation Method

In tablet formulation, binders are essential for ensuring proper powder mix, granulation and overall tablet quality. Variations in binder quality and concentration can impact drug bioavailability, strength and manufacturing processes. The inconsistency in bioavailability and therapeutic response of metronidazole from different manufacturers highlights the importance of binder selection in tablet formulation. This study evaluates the impact of different binding agents on tablet quality. The optimum binder concentration for each of the binders was assessed to obtain suitable concentration that was used to prepare metronidazole tablets. Metronidazole tablets were formulated with four different binder vis, acacia, gelatine, PVP, maize starch at 3% concentration using wet granulation method after which the tablet properties were evaluated. Metronidazole powder exhibited poor flow indices, as indicated by angle of repose: 39.92 ± 1.85, Carr’s compressibility index (CI): 20.13 ± 0.28 and Hausner’s ratio (Hr): 1.26 ± 0.01, whereas its granules exhibited good flow properties. The crushing strength (CS), friability (FR), disintegration time (DT) (CSFR/DT) ratio for batches showed values in 3% binder concentration, indicating higher strength as compared to other concentrations. There was a significant increase (P &lt; 0.05) in the CSFR/DT ratio for gelatine (2.22) in formulation F2 compared to maize starch in Formulation F4. The formulated tablets with the various binders have met with the British Pharmacopeial criteria of 80% drug release from uncoated immediate-release tablets. Amongst the four binders, gelatine was found to be the best in the formulation of robust metronidazole tablets by wet granulation method at an optimised concentration of 3% w/w. Tablets produced with gelatin exhibited greater mechanical strength than those produced with other binders, while also demonstrating a slightly longer DT. Metronidazole tablets produced with gelatine have met the British Pharmacopeial requirements including an acceptable in-vitro drug release profile.

Power generation characteristics and optimum alcohol concentration in bio-direct alcohol fuel cell using chitin family electrolyte

Direct alcohol fuel cells (DAFCs) have the potential to become the next-generation portable energy device. However, the development of DAFC requires the explore new electrolytes without fuel crossover. In this study, DAFC with bio-electrolyte have been fabricated and their characteristics have been investigated. Ethanol impermeability measurements revealed that the crossover of ethanol in the chitin and chitosan electrolytes is extremely low. This result indicates that the chitin family electrolyte has the potential of DEFC electrolytes. Furthermore, DAFCs using the chitin electrolyte have been investigated for various alcohol fuels (methanol, ethanol, 1-propanol, and 1-butanol fuels), and the optimum fuel concentrations to achieve the maximum power density in these DAFCs have been determined. In addition, these results and viscosity measurements clarify the optimum alcohol fuel concentration can be obtained by adding the water molecules required for the proton generating reaction to the water molecules required to stabilize alcohol in water.

Humic acid as eco‐friendly corrosion inhibitor for EH40 ship plate steel

In this study, a new type of green corrosion inhibitor, namely, sodium humate (SH), was extracted from humus soil, which is a natural humus plant, by dissolution‐neutralization, and then used for corrosion inhibition of low carbon steel in seawater. The corrosion inhibition performance of SH on low carbon steel EH40 in seawater was tested by weight loss method and electrochemical technology. The surface and corrosion products of low carbon steel were observed and analyzed by scanning electron microscope (SEM), atomic force microscope (AFM), contact angle and X‐ray photoelectron spectroscopy (XPS). The results show that SH is a mixed corrosion inhibitor, and the optimum concentration is 2 g L−1. At this concentration, the inhibition rate can reach 93.6%. It mainly affects the semi‐reaction of cathodic corrosion. By forming a corrosion protection layer with uniform adsorption on the surface of EH40 steel, EH40 steel becomes more resistant to seawater corrosion.

Effects of phytase inclusion in diets containing rice protein concentrate (RPC) on the nutrient digestibility, growth and chemical characteristics of rohu (Labeo rohita).

The objective of the current study was to assess the impact of dietary phytase supplementation on Labeo rohita fingerlings and to examine the effects on growth, nutrient digestibility and chemical characteristics of diets containing rice protein concentrate (RPC) as a major protein source. Six experimental diets were made, i.e., a positive control (fishmeal-based diet with no phytase), FM0; a negative control (RPC-based diet with no phytase), RPC0; and four supplemental phytase levels (250, 500, 1000, and 2000 FTU/kg). Fingerlings with an average weight of 9.42 ± 0.02 grams (mean ± SD) were randomly distributed into six experimental groups of three replicates, each containing 25 fish per tank (75 liters of water), provided with experimental diets at a rate equivalent to 5% of their body weight for 90 days, and uneaten feed was collected after 2 hours to determine feed consumption. The feces were collected before feeding to estimate digestibility. Phytase in combination with the RPC-based diet significantly (p < 0.05) enhanced phytate phosphorus in vitro hydrolysis; growth performance; nutrient (crude protein, crude fat, moisture and gross energy) and mineral (P, Ca, Mg, Na, K, Zn, Mn and Cu) digestibility; digestive enzyme (protease, lipase and amylase) activity; and mineral deposition up to 1000 FTU/kg phytase. However, the hepatosomatic and viscerosomatic indices and carcass composition were not influenced (p > 0.05) by phytase supplementation. Increasing phytase supplementation in the RPC-based diets led to a significant (p < 0.05) decrease in the serum biochemical parameters (alkaline phosphatase activity, aspartate aminotransferase, alanine aminotransferase), which resulted in improved liver health. In conclusion, phytase-supplemented RPC-based diets improved the growth, mineral/nutrient digestibility, digestive enzymes, serum biochemistry, and mineral deposition of L. rohita fingerlings up to 1000 FTU/kg. Broken line regression analysis revealed that the optimum phytase concentration in the RPC-based diet for L. rohita was 874.19 FTU/kg.

Low-flammability carbon fiber reinforced composites based on low-viscosity phosphorus-containing epoxy binders for transfer molding methods

This study is the first investigation into the possibility of low viscosity phosphorus-containing epoxy binders using triglycidyl phosphate for carbon fiber-reinforced polymers (CFRPs) production by resin transfer molding (RTM). Rheological studies and flammability evaluations were carried out to determine the optimum concentrations of triglycidyl phosphate in the epoxy binder. The introduction of triglycidyl phosphate into the epoxy composition was shown to produce self-extinguishing epoxy polymers. In addition, the curing kinetics of the phosphorus-containing epoxy binder was evaluated using differential scanning calorimetry (DSC) to optimize the curing process. The impregnation process of the product in the PAM-RTM software package was modeled to evaluate the possibility of obtaining large-size CFRP parts based on the developed binder by transfer molding methods. The physical-mechanical and fire-resistant tests of CFRPs showed significant improvement in flame-retardant properties in the modified samples, while maintaining high values of strength and elastic modulus. The study concluded that the introduced triglycidyl phosphate significantly affects the binder properties by reducing the viscosity, and increasing the flame retardancy, thus opening a promising direction for developing advanced composite materials.

Extraction, Characterisation and Evaluation of Antioxidant and Probiotic Growth Potential of Water-Soluble Polysaccharides from Ulva rigida Macroalgae.

Ulva rigida green macroalgae contain a variety of polysaccharides. A recent study investigated the optimum concentration and yield of polysaccharide extraction from oven-dried U. rigida biomass using a water-soluble polysaccharide extraction method that adhered to safety standards. This study utilised complete factorial experiments to examine the effects of varying factors on polysaccharide extraction. Results showed a positive correlation between increased levels of all factors and higher polysaccharide extraction yield. This study also found that the main factors and their interaction had a significant impact on the extracted polysaccharides from U. rigida. The highest polysaccharide content and yield were 9.5 mg/mL and 189 mg/g, respectively. Water-soluble polysaccharides demonstrated the presence of reducing sugar (8 mg/g), phenolics (0.69 mg/g) and flavonoids (1.42 mg/g) and exhibited antioxidant properties. Results revealed that freeze-dried polysaccharide powders were primarily composed of the monosaccharide rhamnose. Preliminary results on the effect of these powders on probiotics demonstrated that supplementation of polysaccharides from U. rigida promoted viable Lactobacillus rhamnosus ATCC 53103 growth during cultivation. This discovery has the potential to revolutionise the human food industry and promote the development of functional ingredients for novel and future food products, with numerous applications in the nutraceutical and pharmaceutical industries.

Highly Oriented FAPbI3 via 2D Ruddlesden Popper Perovskite Template Growth

Abstract2D perovskites are demonstrated as the growth template for the modulation of phase transition and crystallization of formamidinium lead triiodide (FAPbI3). However, it is challenging to obtain highly oriented α‐FAPbI3 and regulate crystallization at the bottom of the FAPbI3 film. Here, a 2D (BA)2PbI4 layer with preferred orientation is introduced to perform as the bottom template for the quasi‐epitaxial growth of FAPbI3, which triggers the α‐FAPbI3 perovskite formation. Owing to the assembly of [PbI6]4− octahedral on the 2D template, the highly (100) oriented FAPbI3 perovskites from the bottom to the top are attained. At the optimum concentration, 2D perovskites gradually vanish due to the extrusion of BA+ cation from the template, which guarantees the charge transport at the bottom. Consequently, the strategy effectively promotes film quality and suppresses non‐radiative recombination. The efficiency of perovskite solar cells (PSCs) is promoted from 23.06% to 24.78%.

Extracellular Endoglucanase and Exoglucanase Enzymes Production by Trichoderma viride Utilizing Olive Mill Wastewater (OMW) in liquid fermentation

Background:The cellulase enzyme is one of the most industrially important enzymes. Its cost represents a significant barrier to other valuable commercial products. Reducing the cost of cellulase production is an important approach. Objectives: For this purpose, this work investigated the production of cellulase enzyme using olive oil production waste (olive mill wastewater (OMW). Materials and methods: The ability of Trichoderma viride to utilize OMW as a substrate for cellulase production was studied. Optimization of cellulase production was investigated to find out the optimum OMW concentration, agitation speed, aeration rate, and cellulose addition. Results:The results showed that 75% v/v OMW submerged shake flask culture was the most suitable culture for T. viride growth and cellulase enzyme production (0.82 U/ml endoglucanase activity and 0.25 U/ml exoglucanase activity). When this culture was supplemented with cellulose, the activity of endoglucanase and exoglucanase was significantly improved (10.24 U/ml and 2.17 U/ml respectively).The agitation speed of 200 rpm enhanced the production to reach 9.1 U/ml of endoglucanase and 6.38 U/ml of exoglucanase. The effect of the aeration rate on enzyme production was studied under batch cultivation. The highest cellulase activity was at 2.0 vvm, where the endoglucanase and exoglucanase activities were 55.96 U/ml and 32.62 U/ml respectively. Conclusions: Therefore, it is claimed that OMW is a suitable medium for cellulase enzyme production after optimization of the process.

Remote optical thermometry by two-dimensional LiAl5O8:Cr3+ luminescence sensor probe

Pure-phase LiAl5O8:Cr3+ leaf-like particles were synthesized by combustion synthetic route at various concentrations. Both sharp peaks and broad emission photoluminescence are apparent even at room temperature. The most optimum doping concentration of 0.75 % based on lifetime and emission intensity was chosen. Peaks of different configurations were separated by deconvolution from 120 K to 680 K, where 4T2 peak increases in temperature to the expense of the sharp 2E emissions, giving luminescence intensity ratio (LIR) relative sensitivity of 2.8 % K−1 at room temperature. Large separation between Cr3+ R lines marks their LIR as perspective at low temperatures. At high temperatures luminescence lifetime provided for 0.8 % K−1 sensitivity, while line-shift and bandwidth methods are not sensitive enough for thermometric applications. Deconvolution of peaks enabled for 10 % more precise estimation of Debye temperature (679 K).

Tough double-network hydrogels with excellent frictional properties based on the in-suit inhibition strategy for biomedical applications

Osteoarthritis (OA) is one of the most common joint disorders all over the world and hydrogels could be an effective tool to solve this problem. In this work, we explore the mechanism of tribology properties of double-network hydrogel (DN hydrogel) under effect of free radical polymerization inhibitors. Fe3+ is added to the DN hydrogel as highly efficient and easily adjustable inhibitor, and the friction coefficient can be reduced to 0.0038 by adjusting the concentration. Even after 6 h of continuous tribological testing, the DN hydrogel remains a surprising sustained superlubricity. Furthermore, the strength of the hydrogel can reach 2.36 MPa, which is 20 times higher than that of the single-network hydrogel (SN hydrogel). The introduction of the inhibitor reduces covalent crosslinking that enables the hydrogel to form a sparser mesh structure conducive to the reduction of the friction coefficient, especially the additional physical cross-linking delivered from the electrostatic interaction between Fe3+ and carboxyl groups increases strength. The optimum concentration of Fe3+ is explored to achieve the synergetic improvement of lubricative and mechanical properties. This work opens innovative technology routes for developing superlubricious and tough hydrogels, which is a brighter future for artificial cartilage applications.

Promoting effect of biogenic AgNPs on Echinops macrochaetus for improving growth parameters and mitigating the toxic effect caused by salinity stress

Nanoparticles may serve as novel plant growth stimulators to improve plant growth as well as protect plants from abiotic stresses. In this study, biogenic silver nanoparticles (AgNPs) were synthesized using the aqueous extract of Fagonia bruguieri and characterized using UV-visible spectroscopy, Zeta potential, transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR). The synthesized AgNPs were employed on Echinops macrochaetus as seeds priming, and plants grown in pots were exposed to salinity stress to assess the ameliorating effects based on various parameters. The growth parameters (shoot length) and biomass (shoot, root and leaves weight) decreased in E. macrochaetus exposed to salinity stress alone (40, 80 and 120 mmol/L NaCl) for 90 days. However, seed priming with a low concentration of AgNPs (40 µmol/L) improved the growth of the plant in terms of biomass, shoot length and chlorophyll content alone as well as ameliorated the toxic effect caused by salinity stress. The mitotic index measured by flowcytometry (FCM) indicated genotoxic effects in plants grown at high concentrations of NaCl (80 and 120 mmol/L) as well as plants obtained with 80 µmol/L AgNPs seed priming and exposed to 120 mmol/L NaCl. Thus, an optimum concentration of AgNPs could be used in E. macrochaetus for production of more biomass by modulating the chlorophyll content, proline and antioxidant enzyme activity.