Saline Medium Research Articles

Enhancement of corrosion protection of metal carbon steel C45 and stainless steel 316 by using inhibitor (Schiff base) in sea water

This research has presented a solution to the problem faced by alloys: the corrosion problem, by reducing corrosion and enhancing protection by using an inhibitor (Schiff base). The inhibitor (Schiff base) was synthesized by reacting of the substrates materials (4-dimethylaminobenzaldehyde and 4-aminoantipyrine). It was diagnosed by infrared technology IR, where the IR spectrum and through the visible beams proved that the Schiff base was well formed and with high purity. The corrosion behavior of carbon steel and stainless steel in a saline medium (artificial seawater 3.5%NaCl) before and after using the inhibitor at four temperatures: 20, 30, 40, and 50 C° was studied by using three electrodes potentiostat. The corrosion behavior was studied by cathode and anode polarization through which all corrosion parameters were investigated which include: corrosion current icorr (1341× 10-7- 5393 × 10-9A/cm2), corrosion potential Ecorr (-1.031- -0.227 mV vs SCE) , corrosion rates CR (0.658-0.007 mm.y-1), inhibition efficiency %IE (92-98%), and energy activation barriers Ea (4.709-26.733 kJ/mole). The thermodynamic and kinetic properties of the corrosion behavior of these two metals under study, which include: enthalpy ∆H*(2.153-24.176 kJ/mole), entropy ∆S*(-197 -156 J/mole), and free Gibbs energy ∆G*(59.87-74.56 kJ/mole) before and after using the inhibitor, were also studied.

Air or Saline? A Propensity Score-Matched Analysis on the Effect of Tissue Expander Fill on Complications in Immediate Breast Reconstruction.

Tissue expander fill medium and volume have implications for the pressure exerted on mastectomy skin flaps. This study evaluated the influence of initial fill medium (air vs. saline) on complications in immediate breast reconstruction within a propensityscore-matched cohort. Patients undergoing immediate tissueexpander-based breast reconstruction with initial intraoperative fill with air were propensity score matched 1:2 to those with saline initial fill based on patient and tissue expander characteristics. Incidence of overall and ischemic complications were compared by fill medium (air vs. saline). A total of 584 patients were included, including 130 (22.2%) with initial fill with air, 377 (64.6%) with initial fill with saline, and 77 (13.2%) with 0 cc of initial fill. After multivariate adjustment, higher intraoperative fill volume was associated with increased risk of mastectomy skin flap necrosis [regression coefficient (RC) 15.7; p = 0.049]. Propensity score matching was then conducted among 360 patients (Air: 120 patients vs. Saline: 240 patients). After propensity score matching, there were no significant differences in the incidences of mastectomy skin flap necrosis, extrusion, reoperation, or readmission between the air and saline cohorts (all p > 0.05). However, initial fill with air was associated with lower incidence of infection requiring oral antibiotics (p = 0.003), seroma (p = 0.004), and nipple necrosis (p = 0.03). Within a propensityscore-matched cohort, initial fill with air was associated with a lower incidence of complications, including ischemic complications after nipple-sparing mastectomy. Initial fill with air and lower fill volumes may be strategies to reducing risk of ischemic complications among high-risk patients.

Cytotoxic effects of different mouthwash solutions on primary human articular chondrocytes and normal human articular cartilage – an in vitro study

ObjectivesTo compare the cytotoxicity of octenidine dihydrochloride and chlorhexidine gluconate at different concentrations on primary human articular chondrocytes and cartilage.Materials and methodsPrimary cultures of human normal adult articular chondrocytes were exposed to octenidine dihydrochloride (0.001562%, 0.003125%, 0.00625%, 0.0125%, 0.025%, 0.05%, and 0.1%), chlorhexidine gluconate (0.003125%, 0.00625%, 0.0125%, 0.025%, 0.05%, 0.1%, and 0.2%), and control (Dulbecco’s modified Eagle medium or phosphate-buffered saline) for 30 s. Normal human articular cartilage explants were exposed to octenidine dihydrochloride (0.1% versus control) and chlorhexidine gluconate (0.1% versus control) for 30 s. The viability of human articular chondrocytes was measured by Trypan blue staining, Cell Proliferation Reagent WST-1, and Live/Dead staining. The proliferation of human chondrocytes was measured using the Cell Proliferation Reagent WST-1. The viability of human articular cartilage explants was measured by using Live/Dead staining.ResultsOctenidine dihydrochloride and chlorhexidine gluconate exposure decreased cell viability and proliferation in a dose-dependent manner in primary human articular chondrocytes. Octenidine dihydrochloride and chlorhexidine gluconate exposure decreased cell viability in human articular cartilage explant cultures.ConclusionThe degree of toxicity varied between octenidine dihydrochloride and chlorhexidine gluconate, with chlorhexidine gluconate being less toxic than octenidine dihydrochloride at the same concentration. Additionally, both octenidine dihydrochloride and chlorhexidine gluconate evaluation had cytotoxic effects on human articular cartilage. Therefore, dosing for the antimicrobial mouthwash ingredients administration would ideally be determined to remain below IC50.Clinical relevanceThese data support the in vitro safety of antimicrobial mouthwashes on primary adult human articular chondrocytes.

Metallogenesis of the Cu-Ni sulfide type mineralization in the Bounhas vein deposit (Eastern Anti-Atlas, Morocco): Insights from ore mineral paragenesis and fluid phases

The Moroccan Anti-Atlas hosts numerous precious metal (Au, Ag, Co, PGE...) and base metal (Cu, Pb, Zn...) mineralizations that are developed in various geological and geodynamic contexts. Some of these mineralizations, such as copper and nickel, are known in the form of deposits at the scale of the Anti-Atlas and are the subject of mining development and exploitation. This is the case of the Bounhas deposit, which is located in the southern part of the Eastern Anti-Atlas, 50 km SE of the city of Alnif. It is characterized by Cu, Ni, Pb and Zn mineralizations, which are essentially hosted in sedimentary terrains of a sandstone-pelitic nature of the upper formation of the second Bani group (Upper Ordovician). These terrains are affected by brittle deformations that have developed faults that host the lenticular vein mineralization in an E-W direction. The arrangement and textural relationships between the mineral phases of the Bounhas deposit have allowed to distinguish two distinct mineralizing events: (i) a primary hydrothermal event subdivided into 3 metalliferous episodes the first, with Fe, characterized essentially by pyrite mineralization in a carbonate gangue (ankerite and siderite); the second with Cu, Ni, As ± Zn ± Pb, precipitates most of the arsenopyrite, sphalerite I, galena I, gersdorffite and chalcopyrite mineralization in a quartz gangue; and the third, with Pb, Zn, and Ba, places galena II and sphalerite II in a barytic gangue. A late supergene alteration event, characterized by the appearance of minerals typical of cementation, sulfation, carbonation and oxidation zones (covellite, native copper, anglesite, malachite, azurite and iron oxides). Moreover, the study of the fluid inclusions associated with the Cu, Ni, As ± Pb ± Zn mineralization from the Bounhas deposit reveals the presence of two types of fluids: (i) a hypersaline fluid, characterized by a salinity varying between 25 and 30 wt% NaCl eq and a homogenization temperature: Th = 200 to 240 °C. This fluid would be responsible for the development of the copper-nickel-arsenic mineralization of this deposit and (ii) a late medium saline fluid (12 to 15 wt% NaCl eq) and a homogenization temperature Th = 80 °C to 120 °C, to which would be attributed the development of the Pb and Zn mineralization of this deposit.

Homocysteine May Decrease Glucose Uptake and Alter the Akt/GSK3β/GLUT1 Signaling Pathway in Hippocampal Slices: Neuroprotective Effects of Rivastigmine and Ibuprofen.

Homocysteine (Hcy) is a risk factor for neurodegenerative diseases, such as Alzheimer's Disease, and is related to cellular and tissue damage. In the present study, we verified the effect of Hcy on neurochemical parameters (redox homeostasis, neuronal excitability, glucose, and lactate levels) and the Serine/Threonine kinase B (Akt), Glucose synthase kinase-3β (GSK3β) and Glucose transporter 1 (GLUT1) signaling pathway in hippocampal slices, as well as the neuroprotective effects of ibuprofen and rivastigmine alone or in combination in such effects. Male Wistar rats (90 days old) were euthanized and the brains were dissected. The hippocampus slices were pre-treated for 30min [saline medium or Hcy (30 µM)], then the other treatments were added to the medium for another 30min [ibuprofen, rivastigmine, or ibuprofen + rivastigmine]. The dichlorofluorescein formed, nitrite and Na+, K+-ATPase activity was increased by Hcy at 30 µM. Ibuprofen reduced dichlorofluorescein formation and attenuated the effect of Hcy. The reduced glutathione content was reduced by Hcy. Treatments with ibuprofen and Hcy + ibuprofen increased reduced glutathione. Hcy at 30 µM caused a decrease in hippocampal glucose uptake and GLUT1 expression, and an increase in Glial Fibrillary Acidic Protein-protein expression. Phosphorylated GSK3β and Akt levels were reduced by Hcy (30 µM) and co-treatment with Hcy + rivastigmine + ibuprofen reversed these effects. Hcy toxicity on glucose metabolism can promote neurological damage. The combination of treatment with rivastigmine + ibuprofen attenuated such effects, probably by regulating the Akt/GSK3β/GLUT1 signaling pathway. Reversal of Hcy cellular damage by these compounds may be a potential neuroprotective strategy for brain damage.

Intelligent anticorrosion coating based on mesostructured BTA@mCeO2/g-C3N4 nanocomposites for inhibiting the filiform corrosion of Zn-Mg-Al coated steel

Filiform corrosion (FFC) challenges the application of Zn-Mg-Al coated steel (ZMA-steel). Herein, a self-healing coating loaded with functionalized mesoporous CeO2 (mCeO2) was developed to suppress FFC for ZMA-steel in saline media. mCeO2 of large specific area readily accommodated benzotriazole and immobilized on g-C3N4 generating a nanofiller (BTA@mCeO2/g-C3N4) for epoxy matrix (EP). Strong barrier of lamellar g-C3N4, releasing BTA from nanofiller and generating Ce cations accounted for the long-term corrosion-resistance and self-healing effect of BTA@mCeO2/g-C3N4/EP system for ZMA-steel. Through taking full advantages of CeO2-based nanofiller, this work may provide an intelligent coating to solve FFC of ZMA-steel.

Mineralization of the Liwu large-scale stratiform copper deposits in Sichuan Province, China: Constraints from fluid inclusions

The Liwu stratiform copper deposit is located in the NW Jianglang dome, western China. Current studies mainly focus on the genetic type and mineralization of this deposit. Detailed fluid inclusion characteristics of metallogenic period quartz veins were studied to reveal the ore-forming fluid features. Laser Raman analysis indicates that the ore-forming fluids is a H₂O-NaCl-CH₄ (-CO₂) system. Fluid inclusions microthermometry shows a homogenization temperature of 181–375°C and a salinity of 5.26%–16.99% for the disseminated-banded Cu-Zn mineralization; but a homogenization temperature of 142–343°C and a salinity of 5.41%–21.19% for the massive-veined Cu-Zn mineralization. These features suggest a medium–high temperature and a medium salinity for the ore-forming fluids. H-O isotopic data indicates that the ore-forming fluids were mainly from the metamorphic and magmatic water, plus minor formation water. And sulfur isotopic data indicates that sulfur was mainly derived from the formation and magmatic rocks. Metallogenesis of the disseminated-banded mineralization was mainly correlated with fluid mixing and water-rock reaction; whereas that of the massive-veined mineralization was mainly correlated with fluid boiling. The genetic type of the deposit is a medium-high temperature hydrothermal deposit related to magmatism and controlled by shear zones. This study is beneficial to understand the stratiform copper deposit.

Modeling of fertilization on the photosynthetic and yield indicators of melon (Cucumis melo L.) under the saline soils of southern Kazakhstan

Recommendations on the use of generalized regional fertilizers for agricultural crops lead to low fertilizer efficiency, and an imbalance of plant nutrition while identifying economic and environmental problems. The use of innovative methods with the modelling of fertilizers with balanced doses of nutrients used based on the needs of crops, the potential of fertility and the degree of soil degradation should be the main condition for sustainable precision farming. Therefore, a field experiment to study the application of mineral fertilizers on melon was carried out under two saline backgrounds of light serozem at a farmer’s field, Maktaaral District, Kazakhstan during 2022. The experiment was laid out in a randomized complete block design (RCBD) with 10 treatments: T1–Control (no fertilizer), T2–N120P80, T3–N120K80, T4–P80K80, T5–N120P80K80, T6–N60P80K80, T7–N180P80K80, T8–N120P120K80, T9–N120P80K120 and T10–N157K256 and N93K96 for a targeted yield of 30 and 20 t/ha on low and medium-saline soils, respectively, each replicated thrice. Ammonium nitrate (34%), double superphosphate (45%) and potassium sulfate (51%) were used as fertilizers. The study of photosynthetic productivity of plants showed that the accumulation of dry biomass (from 1.9 to 10.37 t/ha) and leaf area (from 7.8 to 26.5 m2/ha) adequately changed with changes in doses and ratios of fertilizers. On the low salinity background, high early yields were provided by T5 and T10-10.1 and 10.9 t/ha, against a medium saline background, they were lower than low saline background of 1.7 and 2.3 t/ha, respectively. When modelling the effect of fertilizers on the formation of an early melon crop, the unilateral action of nitrogen fertilizers, the interaction of nitrogen fertilizer with potash fertilizer and the interaction of phosphorus fertilizer with the soil salt concentration have been excluded from the equation as insignificant (P less than 0.05).

Nigella sativa extract phytochemicals: Effective green/bio-active anti-corrosion agent for steel protection in saline media

This research aims to develop a low-VOC silane (sol-gel) coating functionally protected by novel non-toxic metal-organic networks (MONs) based on extracted Nigella sativa bio-molecules/Zinc nitrate. The effectiveness of the silane coating containing the MONs pigment was investigated via electrochemical (i.e., EIS) and accelerated (i.e., salt spray) corrosion experiments. Based on the electrochemical tests' results in the solution phase, an efficiency of 67.8% and a mixed-type corrosion mitigation mechanism were obtained for the hybrid pigment to protect the mild steel against the NaCl media. Moreover, adding the synthesized MONs into the silane coating matrix dramatically increased its protection performance. Fourier-transform infrared spectroscopy (FT-IR) results revealed that the coating’s curing index is affected after the MONs pigment’s inclusion in the silane matrix. The change in the coating curing index increases the silane film crosslinking density, improving coating adhesion to the metallic substrate and then enhancing its anti-corrosion protection performance. The electrochemical tests were employed in the presence of artificial defects to study the active protection performance of the silane layer. Results indicated that the active anti-corrosion protection performance of the silane coating was significantly improved after employing the synthesized MONs in its structure. Adsorbing the inhibitive species in the scratched region of the silane coating and fabricating the inhibitive film at this region is the main protection mechanism, which was illustrated via SEM/EDS analysis.

Sуnthesis of terpene–methacrylic acid copolymers and their effect on the stability of inorganic dispersions in the presence of cationic surfactants

Copolymers of methacrylic acid and natural terpene monomers (α-pinene; β-pinene; ∆3-karene) with the molecular weight of (0.3–0.5)∙104 and a content of carboxyl groups of 14.5–16.3 % were synthesized. For the synthesized copolymers, hydrodynamic radius and the Kuhn segment, which characterizes flexibility of a polymer chain, were determined, as well as the Huggins constant in aqueous and saline solutions, and concentration regions for formation of supramolecular structures. In the presence of a cationic surfactant (benzetonium chloride, Hyamine), depending on the concentration of copolymers in the system, polymer-surfactant complexes were formed in soluble and insoluble forms. It has been shown that the effectiveness of the stabilizing action of soluble complexes with respect to an aqueous dispersion of calcium carbonate increases with an increase in the content of nonpolar groups in the polymer chain. A cationic surfactant (Hyamine) has been proposed as a precipitant in the method for the quantitative determination of carboxyl-containing polymers in aqueous and saline media.

Selenite bioreduction by a consortium of halophilic/halotolerant bacteria and/or yeasts in saline media

Selenium oxyanions are released into environments by natural and anthropogenic activities and are present in agricultural and glass manufacturing wastewater in several locations worldwide. Excessive amounts of this metalloid have adverse effects on the health of living organisms. Halophilic and halotolerant microorganisms were selected for selenium oxyanions remediation due to presence of significant amount of salt in selenium-containing wastewater. Effects of aeration, carbon sources, competitive electron acceptors, and reductase inhibitors were investigated on SeO32− bio-removal. Additionally, NO3−-containing wastewater were exploited to investigate SeO32− remediation in synthetic agricultural effluents. The results showed that the SeO32− removal extent is maximum in aerobic conditions with succinate as a carbon source. SO42− and PO43− do not significantly interfere with SeO32− reduction, while WO42− and TeO32− decrease the SeO32− removal percentage (up to 35 and 37%, respectively). Furthermore, NO3− had an adverse effect on SeO32− biotransformation by our consortia. All consortia reduced SeO32− in synthetic agricultural wastewaters with a 45–53% removal within 120 h. This study suggests that consortia of halophilic/halotolerant bacteria and yeasts could be applied to treat SeO32--contaminated drainage water. In addition, sulphates, and phosphates do not interfere with selenite bioreduction by these consortia, which makes them suitable candidates for the bioremediation of selenium-containing wastewater.

Improving Mechanical Properties of Tendon Allograft through Rehydration Strategies: An In Vitro Study.

Allogenic tendons grafts sourced from intrasynovial tendons are often used for tendon reconstruction. Processing is achieved through repetitive freeze-thaw cycles followed by lyophilization. Soaking the lyophilized tendon in saline (0.9%) for 24 h is the standard practice for rehydration. However, data supporting saline rehydration over the use of other hydrating solutions are scant. The purpose of the current study was to compare the effects of different rehydration solutions on biomechanical properties of lyophilized tendon allograft. A total of 36 canine flexor digitorum profundus tendons were collected, five freeze-thaw cycles followed by lyophilization were performed for processing, and then divided into three groups rehydrated with either saline solution (0.9%), phosphate-buffered saline (PBS), or minimum essential medium (MEM). Flexural stiffness, tensile stiffness, and gliding friction were evaluated before and after allograft processing. The flexural moduli in both fibrous and fibrocartilaginous regions of the tendons were measured. After lyophilization and reconstitution, the flexural moduli of both the fibrocartilaginous and non-fibrocartilaginous regions of the tendons increase significantly in the saline and MEM groups (p < 0.05). Compared to the saline and MEM groups, the flexural moduli of the fibrocartilaginous and non-fibrocartilaginous regions of tendons rehydrated with PBS are significantly lower (p < 0.05). Tensile moduli of rehydrated tendons are significantly lower than those of fresh tendons for all groups (p < 0.05). The gliding friction of rehydrated tendons is significantly higher than that of fresh tendons in all groups (p < 0.05). There is no significant difference in either tensile moduli or gliding friction between tendons treated with different rehydration solutions. These results demonstrate that allograft reconstitution can be optimized through careful selection of hydrating solution and that PBS could be a better choice as the impact on flexural properties is lower.

Hydrochemistry, water quality and health risk assessment of streams in Bismil plain, an important agricultural area in southeast Türkiye

In this study, the water quality of Ambar, Kuruçay, Pamuk and Salat streams, which are the important tributaries of the Tigris River in the Bismil Plain (Diyarbakır, Türkiye) was assessed using 19 physicochemical parameters. Except for a few exceptions, all parameters in the water samples taken from the streams were below the drinking water limit values. Kuruçay Stream had significantly higher TOC, Na+, NO3−, NO2−, Cl− and SO42− levels and lower DO levels than other streams (p < 0.05) due to sewage water discharges, animal manure storage areas near the stream and irrigation return flows. In all streams, Ca–HCO3 was dominant water type. Gibbs diagram indicated that rock weathering is the major factor controlling the hydrochemistry of the streams. According to the results of water quality index (WQI), all sampling stations of Ambar, Pamuk and Salat streams and K1 station of Kuruçay Stream had “good” quality water for drinking purposes, while K2 station of Kuruçay Stream had “poor” quality water. Irrigation indices (permeability index, sodium percentage, magnesium hazard, residual sodium carbonate, Kelley's ratio, sodium adsorption ratio and potential salinity) revealed that all water samples taken from the streams were suitable for irrigation. The water samples from Ambar, Pamuk and Salat streams were in the C2S1 (medium salinity and low alkalinity) category, while the samples from Kuruçay Stream were in the C2S1 and C3S1 (high salinity and low alkalinity) categories. Both hazard quotient and hazard index values of NO3–N, NO2–N and F− for children and adults were found below 1, indicating that adverse health effects are not expected from exposure to these contaminants via water ingestion and dermal contact. The findings of this study showed that the water quality status of Kuruçay Stream is worse as it receives large amounts of irrigation return flows compared to other streams.

Development of a Cost-Effective Process for the Heterologous Production of SARS-CoV-2 Spike Receptor Binding Domain Using Pichia pastoris in Stirred-Tank Bioreactor

SARS-CoV-2 was identified as the pathogenic agent causing the COVID-19 pandemic. Among the proteins codified by this virus, the Spike protein is one of the most-external and -exposed. A fragment of the Spike protein, named the receptor binding domain (RBD), interacts with the ACE2 receptors of human cells, allowing the entrance of the viruses. RBD has been proposed as an interesting protein for the development of diagnosis tools, treatment, and prevention of the disease. In this work, a method for recombinant RBD production using Pichia pastoris as a cell factory in a stirred-tank bioreactor (SRTB) up to 7 L was developed. Using a basal saline medium with glycerol, methanol, and compressed air in a four-stage procedure, around 500 mg/L of the raw RBD produced by yeasts (yRBD) and 206 mg/L of purified (&gt;95%) RBD were obtained. Thereby, the proposed method represents a feasible, simple, scalable, and inexpensive procedure for the obtention of RBD for diagnosis kits and vaccines’ formulation.

Spider Plant (Cleome gynandra L.): An Emerging Weed in the Sweet Corn–Brassica Cropping System

Spider plant (Cleome gynandra L.) is an emerging noxious weed, affecting cultivated vegetables in Queensland, Australia. It is a prolific seed producer, forming large seedbanks with variable seedling emergence. A study was carried out to investigate the seed biology of spider plant, focusing on its seed germination ecology, viz., influence of temperatures, illumination conditions, medium salinity, pH, substrate moisture, burial depth, and after-ripening. Freshly harvested seeds were negatively photoblastic and had combinational dormancy. Improved germination was obtained by physical scarification followed by soaking for 16 h, by dry storage for over 6 months, and by the imbibition of gibberellic acid. Maximum germination percentages of 70 to 80% were recorded under constant darkness at alternating day/night temperatures of 20/30 °C, or with 18 to 27 °C constant temperatures. Spider plant showed a broad tolerance to pH but only moderate salt and moisture stress tolerance, since only 42 and 26% germination were observed with 60 mM NaCl and at −0.40 MPa, respectively. Seeds placed on the soil surface did not germinate, however, at a burial depth of 1.0 to 1.5 cm, which resulted in ca. 80% seedling emergence. These findings will assist land managers to predict seasonal emergence and will aid in deploying management approaches to control this weed.

Mitochondria-Targeted COUPY Photocages: Synthesis and Visible-Light Photoactivation in Living Cells.

Releasing bioactive molecules in specific subcellular locations from the corresponding caged precursors offers great potential in photopharmacology, especially when using biologically compatible visible light. By taking advantage of the intrinsic preference of COUPY coumarins for mitochondria and their long wavelength absorption in the visible region, we have synthesized and fully characterized a series of COUPY-caged model compounds to investigate how the structure of the coumarin caging group affects the rate and efficiency of the photolysis process. Uncaging studies using yellow (560 nm) and red light (620 nm) in phosphate-buffered saline medium have demonstrated that the incorporation of a methyl group in a position adjacent to the photocleavable bond is particularly important to fine-tune the photochemical properties of the caging group. Additionally, the use of a COUPY-caged version of the protonophore 2,4-dinitrophenol allowed us to confirm by confocal microscopy that photoactivation can occur within mitochondria of living HeLa cells upon irradiation with low doses of yellow light. The new photolabile protecting groups presented here complement the photochemical toolbox in therapeutic applications since they will facilitate the delivery of photocages of biologically active compounds into mitochondria.

Genetic Analysis of Maize Response to Salt Stress in Hydroponic Medium

The productivity of maize (Zea mays L.) from the farmers’ fields has been characterized as being low due to salinity among other contributing factors. In this study the use of phenotypic traits as a selection criterion and screening of maize genotypes for tolerance to salt stress was investigated. The objectives of this study were therefore to i) estimate heritability for genotypic response to root and shoot length ii) ascertain an appropriate genotypic maize screening criterion in saline medium and iii) identify tolerant maize genotypes in hydroponic medium. The experiment was set up as 5 x 11 factorial completely randomized design (CRD) with three replications at the University of Zambia, pathology laboratory. Thus 11 genotypes were evaluated in five doses of salinity concentrations giving 55 experimental units. Genotypes exhibited significant differences (P&lt; 0.05) in response to both parameters (root and shoot length) across salinity concentrations. Similarly the response of root and shoot length in different salinity concentration across genotypes was also significant (P&lt; 0.001). The entry based heritability estimate was found to be 0.76 and 0.18 for responses to root and shoot respectively. Shoot length was identified as a key trait to utilize in screening maize genotypes for tolerance to salt stress under hydroponic conditions despite possessing a low heritability estimate. In this study tolerant genotypes to salt stress were identified as ZHYB 2, ZHYB 7 and ZHYB 11.

Chitosan derivatives as surfactant carriers for enhanced oil recovery – Experimental and molecular dynamic evaluations of polymer-surfactant interactions

Surfactant injections in enhanced oil recovery (EOR) are very efficient, lowering the oil-water interfacial tension (IFT) and altering rocks wettability. Although efficient, surfactant injection during EOR process is economically unfeasible due to the high-cost caused by surfactant losses due to adsorption or precipitation on the rock surface. One strategy to reduce these losses during the flooding process is using surfactant carriers such as nanoparticles, emulsions, and polymers. Polymers are good candidates because they can act in transportation, alter rock wettability, and improve sweeping efficiency. Recently, the potential of chitosan derivatives as wettability modifiers of carbonate rocks was demonstrated. This way, using chitosan derivatives as surfactant carriers is an interesting strategy due to its high storage capacity and environment-friendly product. In this study, cationized (TMC) and hydrophobized (TMC-C14) chitosan derivatives were synthesized, characterized, and evaluated as OADA (oleic acid diethanolamide) surfactant carriers for EOR. Interfacial tension tests evaluated the potential of OADA in low and high salinity medium. Particle size measurements, done by dynamic light scattering, and molecular dynamics simulations (MD), allowed the understanding of the interaction between TMC or TMC-C14 and the surfactant. The controlled surfactant release at the water/oil interface by chitosan derivatives was evaluated by IFT measurements and MD simulations. The results showed that OADA is an excellent surfactant whose IFT reaches 10−2 mN/m, and chitosan derivatives were able to carry the surfactant to the site containing the oil. Thus, chitosan derivatives are an efficient supramolecular surfactant carrier system that can minimize surfactant losses by adsorption on the rock surface, being an interesting alternative for EOR application.

Synthesis and rheological properties of water soluble ionic copolymers as modifier fluids at high temperature and saline media

AbstractPolymer flooding depicts an interesting strategy to improve the enhanced oil recovery (EOR). This work aims with the synthesis of ionic thermo‐responsive copolymers able to be used as rheological modifiers for EOR under harsh conditions (250,000 ppm of NaCl at 150°C). Copolymers composed of different molar ratio of acrylamide, N‐isopropylacrylamide and 2‐acrylamide‐2‐methyl‐1‐propanesulfonic acid were prepared in aqueous media via free radical polymerization at 50°C using 4,4′‐azobis(‐4″‐cyanopentanoic) acid (ACPA) as initiator. Nuclear magnetic resonance analyses demonstrated the structure and molar composition of synthesized copolymers. Rheological measurements performed at different concentration from 1 to 8 wt% demonstrated an increase in the viscosity from 2000 to 600,000 mPa.s. Aqueous mixtures of polymer at 5 wt% and NaCl at different concentration (5, 10, 15, 20, and 25 wt%) was analyzed. Copolymer ([PAM]/[PNIPAM] = 50/50) displayed a phase separation at 15 wt% of NaCl. Solutions of polymer at 5 and 25 wt% of NaCl were heated at 150°C for 72 h. Results revealed both thermal stability and saline tolerance of copolymers [PAM]/[PNIPAM]/[PAMPS‐Na] = 25/25/50, 35/35/30, and 50/0/50 under harsh conditions with the absence of phase separation of the brine polymer solutions.

On the Use of Polymer Inclusion Membranes for the Selective Separation of Pb(II), Cd(II), and Zn(II) from Seawater.

The synthesis and optimization of polymeric inclusion membranes (PIMs) for the transport of Cd(II) and Pb(II) and their separation from Zn(II) in aqueous saline media are presented. The effects of NaCl concentrations, pH, matrix nature, and metal ion concentrations in the feed phase are additionally analyzed. Experimental design strategies were used for the optimization of PIM composition and evaluating competitive transport. Synthetic seawater with 35% salinity, commercial seawater collected from the Gulf of California (Panakos®), and seawater collected from the beach of Tecolutla, Veracruz, Mexico, were employed. The results show an excellent separation behavior in a three-compartment setup using two different PIMs (Aliquat 336 and D2EHPA as carriers, respectively), with the feed phase placed in the central compartment and two different stripping phases placed on both sides: one solution with 0.1 mol/dm3 HCl + 0.1 mol/dm3 NaCl and the other with 0.1 mol/dm3 HNO3. The selective separation of Pb(II), Cd(II), and Zn(II) from seawater shows separation factors whose values depend on the composition of the seawater media (metal ion concentrations and matrix composition). The PIM system allows S(Cd) and S(Pb)~1000 and 10 < S(Zn) < 1000, depending on the nature of the sample. However, values as high as 10,000 were observed in some experiments, allowing an adequate separation of the metal ions. Analyses of the separation factors in the different compartments in terms of the pertraction mechanism of the metal ions, PIMs stabilities, and preconcentration characteristics of the system are performed as well. A satisfactory preconcentration of the metal ions was observed after each recycling cycle.