Aqueous Research Articles

Enhanced Removal of Brine From Porous Structures by Supercritical CO2.

Supercritical CO2 (sCO2) removes water from brine held in pumice stone at levels well above the solubility of water in sCO2. The higher water removal results from a combination of passive emulsification of water in sCO2 and viscous fingering of sCO2 through the saturated pumice. This leads to higher levels of salt deposition than that expected from solubility considerations alone. These deposits could impact the injectivity of sCO2 as well as its movement in the subsurface. The finding that the water concentration in sCO2 is not necessarily capped at the solubility limit should influence the parametrization of injection models.

Predicting the Electrophoretic Mobility of Charged Particles in an Aqueous Medium.

Electrophoresis of charged particles has important applications in biochemical separation processes. The mobility of these particles depends on the surrounding electric double layer (EDL), which is impacted by solvent restructuring because of hydration interactions. Nevertheless, most theoretical estimates ignore such interactions during computation of the electrophoretic mobility. Here, we employ a complementary blend of mean-field analysis and molecular dynamics simulations performed for a peptide-G-quadruplex complex to assess how hydration interactions alter the mobility of a charged particle in an aqueous medium. These interactions are seen to stabilize the EDL, resulting in more significant localized counterion concentrations while strengthening the ensuing electrokinetic flow. The ordering of ions near the particle surface is obtained only upon including hydration interaction, revealing that the hydration water molecules act as a glue for forming a stable EDL, a key finding of this work. Conversely, the observed microstructure of ions near the charged surface as obtained from our theory establishes a bridge link between the micro and continuum model. The presence of larger counter ions enhances the drag on the particle, thus restricting its mobility. The mobility also becomes dependent on size, which may be useful for isolating a wide array of biomolecules. The impact of hydration interactions intensifies with increases in particle size, surface charge density, and bulk ion concentration.

Soybean molasses can be used as a substitute for corn in grazing beef cattle supplements during the rainy season.

Soybean molasses (SBMO) is a byproduct derived from the production of soy protein concentrate, obtained through solubilization in water and alcohol. The utilization of SBMO as an animal feed ingredient shows promising potential, primarily due to its low cost and as a potential energy concentrate. This study aimed to assess the intake, digestibility, ruminal parameters (pH and ruminal ammonia - NH3), nitrogen retention (NR) and microbial protein synthesis in grazing beef cattle supplemented with SBMO as a substitute for corn during the rainy season. Five Nellore (10-month-old) bulls with an average initial weight of 246 ± 11.2kg were utilized in a 5 × 5 Latin square design. The animals were housed in five paddocks, each consisting of 0.34ha of Marandu grass (Urochloa brizantha). Five isonitrogenous protein-energy supplements (300g crude protein [CP]/kg supplement) were formulated, with SBMO replacing corn at varying levels (0, 0.25, 0.50, 0.75, or 1.00g-1g). The supplements were provided daily at a quantity of 2.0kg-1 animal. The inclusion of SBMO at any level of corn substitution did not significantly affect the intake of pasture dry matter or total dry matter (P > 0.10). Likewise, the intake of CP and, consequently, the ruminal concentration of NH3 did not differ among the SBMO levels. Increasing the inclusion of SBMO did not have a significant impact on NR (P > 0.10), indicating that animals receiving supplements containing 100% SBMO as a substitute for corn may perform similarly to animals receiving supplements with 100% corn (0% SBMO). Soybean molasses represents a viable alternative energy source for grazing beef cattle during the rainy season and can entirely replace corn without adversely affecting animal nutritional performance.

Reversible Hydrophobic Deep Eutectic Solvent-Based Uranyl-Sensing Optode Film in Aqueous Streams: Color Transformation and Reusability.

A hydrophobic deep eutectic solvent (HDES)-based optode was designed for the preconcentration and determination of the UO22+ ion in aqueous media using spectroscopic techniques [energy-dispersive X-ray fluorescence (EDXRF) and solid-state absorption]. The optode was developed by incorporation of HDES (tri-n-octyl phosphine oxide and decanoic acid in an equimolar ratio), tri-(2-ethylhexyl) phosphate, and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol into a cellulose triacetate matrix. Characterization studies were carried out using different techniques to understand the roles of HDES as a plasticizer, UO22+ extractant, and Br-PADAP immobilizer. Uptake studies revealed that the optimal pH was 3 and sorption followed the type II adsorption isotherm. Uranium in the U-sorbed optode can be directly analyzed over a large concentration range of 0.021 × 10-3-2.1 × 10-3 Mol L-1 using EDXRF. The optode film exhibited a linear dynamic range of 0.84 × 10-6-84 × 10-6 Mol L-1 for uranium, with a lowest limit of detection of 0.084 × 10-6 Mol L-1 by colorimetric analysis. This optode-based method was employed for seawater analysis for its UO22+ concentration without any matrix separation, and the concentration was found to be 1.30 ± 0.06 × 10-8 Mol L-1. The optode exhibited better selectivity for UO22+ in the presence of various cations including Sr2+ and Cs+ in an aqueous medium. Compared to other prevailing optical sensors, this optode performed better in terms of key factors like pH, equilibration time, reusability, and detection limit.

Effective Thermoelectric Properties with Polyselenophene/CuxS Composites

In this study, polyselenophene (PSe), which has more raw materials, lower cost, and can be processed more easily than inorganic thermoelectric materials, was synthesized as a polymeric thermoelectric material with a simple method by chemical oxidative polymerization in aqueous medium. Copper sulfide (CuxS) was synthesized and taken from it in different ratios compared to PSe, PSe/CuxS composites were prepared. The Seebeck coefficient of PSe is 160 μVK-1, while that of PSe/CuxS composite containing 30% CuxS is 410 μVK-1. The PSe/CuxS3 composite with 30% CuxS had the highest Seebeck coefficient and power factor, measuring 410 μVK-1 and 5043 μWm-1K-2, respectively. The electrical conductivity of PSe and PSe/CuxS composites obtained in this study is relatively high, ranging from 10 - 405 Scm-1. PSe and its composites were characterized by FTIR, UV-Vis., XRD, TGA, EDX, and FESEM.

A Fluorescent Probe Derived from L‐Tryptophan for Copper (II) Ion Detection in Aqueous Media

A Fluorescent Probe Derived from L‐Tryptophan for Copper (II) Ion Detection in Aqueous Media

The Synergistic Effect of Huangqi Gegen Decoction on Thrombosis relates to the Astragalus Polysaccharide-improved Oral Delivery of Puerarin

Ethno-pharmacological relevanceHuangqi Gegen decoction (HGD), which comprises Astragali Radix (AR) and Puerariae Radix (PR), is widely used to treat thrombosis in China. However, the mechanism underlying its synergistic effect in thrombosis treatment remains unclear. Aim of the studyFollowing PR administration, low plasma exposure was reported for its primary ingredients. In this regard, this study examined the effect of AR on PR's antithrombotic efficacy with respect to the impact of Astragalus Polysaccharide (APS) on the oral delivery of Puerarin (PUE). Materials and methodsTo evaluate the synergistic effect of HGD, a thrombus mice model was established via intraperitoneal injection of carrageenan. After treatment, histopathological observations were made, and the proportion of thrombus length in the tail, as well as the plasma APTT, PT, INR, and FIB levels, were detected. Molecular docking was employed to assess the PR ingredients that could inhibit the HMGB1/NF-κB/NLRP3 pathway. The Pharmacokinetics of PR ingredients in rats were also compared between the PR and HGD groups. Moreover, the effect of APS on the solubility, intestinal absorption, and pharmacokinetics of PUE was evaluated. Furthermore, the impact of APS on the antithrombotic efficacy of PUE was assessed. ResultsIn mice, AR enhanced the antithrombotic effect of PR. This improved PR effect was associated with isoflavones-induced downregulation of the HMGB1/NF-κB/NLRP3 pathway. The synergistic effect resulting from the compatibility of HGD components was primarily achieved by improving the plasma exposure of PR isoflavones. Specifically, APS enhanced PUE's water solubility through the formation of self-assembly Nanoparticles, increasing its intestinal absorption and oral bioavailability, which, in turn, suppressed the HMGB1/NF-κB/NLRP3 pathway, thus improving its antithrombotic effect. ConclusionsOur findings revealed that APS improved PUE's plasma exposure, enhancing its inhibitory effect on the HMGB1/NF-κB/NLRP3 pathway. This mechanism presents a key aspect of the synergistic effect of HGD compatibility in thrombosis treatment.

Microfluidic extensional flow device to study mass transfer dynamics in the polymer microparticle formation process.

Polymer microparticles are often used to encapsulate drugs for sustained drug-release treatments. One of the ways they are manufactured is by using a solvent extraction process, in which the polymer solution is emulsified into an aqueous bulk phase using a surfactant as a stabilizing agent, followed by the removal of the solvent. The radius of a polymer drop decreases as a function of time until the polymer reaches the gelling point, after which it is separated and dried. Among the various operating parameters, the rate of solvent extraction is a critical step that affects the morphology and porosity, and consequently, the kinetics of drug release. But a fundamental mechanistic understanding of the solvent extraction dynamics as a function of shear is still unexplored. In this study, we have developed an experimental mass transfer model to predict the extraction by using the microfluidic extensional flow device (MEFD) to probe the shear and extraction dynamics at the level of a single drop in a linear extensional flow field. We used a computer-controlled feedback algorithm to manipulate the flow field and hydrodynamically trap a Hele-Shaw drop and observe the extraction process. For the polymer solution, we used a biocompatible polymer, poly-lactic-co-glycolic acid (PLGA) with ethyl acetate (EtOAc) as the solvent. Our experiments were conducted by varying the extensional rate (G) in the channel from ∼0.1 s-1 to ∼10 s-1, and using an analytical solution of the flow field, we captured the dissolution process and measured the change in drop radius (R) with time (t). Interestingly, we initially observed a short-time asymptote R ∼ t, and later the long-time asymptote of R = constant; both trends were physically explained. The transport model developed in this work can be used to predict extraction rates and polymer microparticle composition for any polymer-solvent system. This work is also an important contribution to the literature on convective mass transfer in partially miscible emulsions.

Effect of ultrafine grinding on the structure and physical properties of pregelatinized rice starch.

This study used a combination method of ultrafine grinding and pregelatinization to modify rice starch (RS) to delay its retrogradation and provide a rationale for prolonging rice product shelf life. The structure and physicochemical properties of the pregelatinized ultrafine grinding rice starch (PURS) were compared with those of RS, ultrafine grinding rice starch (URS), and pregelatinized rice starch (PRS). The microstructure, molecular weight, branched starch length distribution, short-range order, crystal structure, and physical properties of RS, URS, PRS, and PURS were analyzed, respectively. Results showed that RS, URS, PRS, and PURS granules exhibited similar spherical or polygonal shapes, and the content of amylose and short-branched starch in PURS increased compared with RS, URS, and PRS. Furthermore, the cross-polarization of PRS and PURS disappeared. Long-chain amylopectin and average molecular weight of PURS decreased significantly after ultrafine grinding. Our study suggested reduced breakdown value and setback value and improved gel stability, and PURS was beneficial for delaying retrogradation compared to RS, URS, and PRS. The ultrafine grinding method improved the water swelling capacity (WSC), solubility, pasting properties, and gelation properties of PRS. The hardness of PURS was reduced by ultrafine grinding. These suggest that the combination of ultrafine grinding and pregelatinization could improve the properties of RS. Pearson's correlation analysis showed that the structure of PURS significantly influenced the physicochemical properties. The present study was helpful in better understanding the importance of ultrafine grinding in improving the anti-retrogradation of PURS and provided new insights into extending the shelf life of rice products by ultrafine grinding and pregelatinization.

Application of Generative Artificial Intelligence in Predicting Membrane Partitioning of Drugs: Combining Denoising Diffusion Probabilistic Models and MD Simulations Reduces the Computational Cost to One-Third.

The optimal interaction of drugs with plasma membranes and membranes of subcellular organelles is a prerequisite for desirable pharmacology. Importantly, for drugs targeting the transmembrane lipid-facing sites of integral membrane proteins, the relative affinity of a drug to the bilayer lipids compared to the surrounding aqueous phase affects the partitioning, access, and binding of the drug to the target site. Molecular dynamics (MD) simulations, including enhanced sampling techniques such as steered MD, umbrella sampling (US), and metadynamics, offer valuable insights into the interactions of drugs with the membrane lipids and water in atomistic detail. However, these methods are computationally prohibitive for the high-throughput screening of drug candidates. This study shows that applying denoising diffusion probabilistic models (DDPMs), a generative AI method, to US simulation data reduces the computational cost significantly. Specifically, the models used only partial (one-third) data from the US simulations and reproduced the complete potential of mean force (PMF) profiles for three FDA-approved drugs (β2-adrenergic agonists) and ∼20 biologically relevant chemicals with known experimentally characterized bilayer locations. Intriguingly, the model can predict the solvation-free energies for partitioning and crossing the bilayer, preferred bilayer locations (low-energy well), and orientations of the ligands with high accuracy. The results indicate that DDPMs can be used to characterize the complete membrane partitioning profile of drug molecules using fewer umbrella sampling simulations at select positions along the bilayer normal (z-axis), irrespective of their amphiphilic-lipophilic-cephalophilic characteristics.

Elucidating the roles of electrolytes and hydrogen bonding in the dewetting dynamics of the tear film

This study explores the impact of electrostatic interactions and hydrogen bonding on tear film stability, a crucial factor for ocular surface health. While mucosal and meibomian layers have been extensively studied, the role of electrolytes in the aqueous phase remains unclear. Dry eye syndrome, characterized by insufficient tear quantity or quality, is associated with hyperosmolality, making electrolyte composition an important factor that might impact tear stability. Using a model buffer solution on a silica glass dome, we simulated physiologically relevant tear film conditions. Sodium chloride alone induced premature dewetting through salt crystal nucleation. In contrast, trace amounts of solutes with hydroxyl groups (sodium phosphate dibasic, potassium phosphate monobasic, and glucose) exhibited intriguing phenomena: quasi-stable films, solutal Marangoni-driven fluid influx increasing film thickness, and viscous fingering due to Saffman-Taylor instability. These observations are rationalized by the association of salt solutions with increased surface tension and the propensity of hydroxyl-group-containing solutes to engage in significant hydrogen bonding, altering local viscosity. This creates a viscosity contrast between the bulk buffer solution and the film region. Moreover, these solutes shield the glass dome, counteracting sodium chloride crystallization. These insights not only advance our understanding of tear film mechanics but also pave the way for predictive diagnostics in dry eye syndrome, offering a robust platform for personalized medical interventions based on individual tear film composition.

A Nanoencapsulated Ir(III)-Phthalocyanine Conjugate as a Promising Photodynamic Therapy Anticancer Agent.

Despite the potential of photodynamic therapy (PDT) in cancer treatment, the development of efficient and photostable photosensitizing molecules that operate at long wavelengths of light has become a major hurdle. Here, we report for the first time an Ir(III)-phthalocyanine conjugate (Ir-ZnPc) as a novel photosensitizer for high-efficiency synergistic PDT treatment that takes advantage of the long-wavelength excitation and near infrared (NIR) emission of the phthalocyanine scaffold and the known photostability and high phototoxicity of cyclometalated Ir(III) complexes. In order to increase water solubility and cell membrane permeability, the conjugate and parent zinc phthalocyanine (ZnPc) were encapsulated in amphoteric redox-responsive polyurethane-polyurea hybrid nanocapsules (Ir-ZnPc-NCs and ZnPc-NCs, respectively). Photobiological evaluations revealed that the encapsulated Ir-ZnPc conjugate achieved high photocytotoxicity in both normoxic and hypoxic conditions under 630 nm light irradiation, which can be attributed to dual Type I and Type II reactive oxygen species (ROS) photogeneration. Interestingly, PDT treatments with Ir-ZnPc-NCs and ZnPc-NCs significantly inhibited the growth of three-dimensional (3D) multicellular tumor spheroids. Overall, the nanoencapsulation of Zn phthalocyanines conjugated to cyclometalated Ir(III) complexes provides a new strategy for obtaining photostable and biocompatible red-light-activated nano-PDT agents with efficient performance under challenging hypoxic environments, thus offering new therapeutic opportunities for cancer treatment.

N,N-Disubstituted 4-sulfamoylbenzoic Cid Derivatives as Inhibitors of Cytosolic Phospholipase A2α: Synthesis, Aqueous Solubility, and Activity in a Vesicle and a Whole Blood Assay.

Cytosolic phospholipase A2α (cPLA2α) is the key enzyme that initiates the arachidonic acid cascade through which proinflammatory lipid mediators can be formed. Therefore, cPLA2α is considered an interesting target for the development of anti-inflammatory drugs. Although several effective inhibitors of the enzyme have been developed, none of them has yet reached clinical application. Recently, we have prepared new 4-sulfamoylbenzoic acid derivatives based on a cPLA2α inhibitor found in a ligand-based virtual screening. The most effective of these compounds were now subjected to further variations in which the substitution pattern on the sulfamoyl nitrogen atom was changed. The new compounds were tested in vitro in a vesicle assay for cPLA2α inhibition as well as for their water solubility, metabolic stability, and selectivity towards related enzymes. In addition, they were evaluated ex vivo in a whole blood assay in which metabolites of the arachidonic acid cascade formed after activation of cPLA2α were quantified using a combined online dilution/online solid phase extraction HPLC-MS method. Inhibitors with submicromolar inhibitory in vitro potency were found with favourable water solubility and selectivity. However, their efficacy did not match that of the highly effective, known, structurally related cPLA2a inhibitor giripladib, which was also tested as a reference. One advantage of some of the new compounds compared to giripladib was their significantly improved water solubility. When analyzing the substances in the ex vivo whole blood assay, it was found that the obtained inhibition data correlated better with the in vivo results when the phorbol ester 12-Otetradecanoylphorbol-13-acetate was used for activation of the enzyme in the blood cells instead of the calcium ionophore A23187. New compounds with good activity towards cPLA2α and reasonable physicochemical properties were identified. Overall, the results obtained could be helpful in the development of clinically applicable inhibitors of this enzyme.

Oxidative degradation of thiocyanate via activation of persulfate by CuO/α-MnO2 composite: Effect of calcination temperature

In this study, a highly efficient CuO/α-MnO2 bimetallic catalyst was synthesized by hydrothermal and calcination methods and employed as a peroxydisulfate (PDS) activator for the degradation of thiocyanate (SCN−) in aqueous phase. The effect of calcination temperature on the catalytic performance of CuO/α-MnO2 and the mechanism of the CM350/PDS system were studied. Under optimal conditions, almost 100 % of SCN− (100 mg/L) was degraded within 90 min. XRD, XPS, Raman, and H2-TPR analyses revealed that the catalytic performance was enhanced in the CM350 catalyst due to the formation of M-O-Cu+-like structures (M = Mn3+, Mn4+, Cu2+) through the combination of α-MnO2 with CuO. The structures exhibit excellent redox ability and facilitate electron transfer between Cu and Mn elements, thereby improving the activation effect of PDS. Besides, the Cu1.5Mn1.5O4 generated from the high calcination temperature was not conducive to the SCN− degradation reaction. Moreover, the mechanism study indicated that SO4·-, ·OH, and the electron transfer pathway mainly accounted for the SCN− degradation. This study provides some guidance for the synthesis of PDS activation materials and the treatment of industrial wastewater by an advanced oxidation process.

Halogen‐Bonded Organic Frameworks (XOFs) Based on N⋅⋅⋅Br+⋅⋅⋅N Bonds: Robust Organic Networks Constructed by Fragile Bonds

AbstractOrganic frameworks face a trade‐off between the framework stability and the bond dynamics, which necessitates the development of innovative linkages that can generate stable frameworks without hindering efficient synthesis. Although iodine(I)‐based halogen‐bonded organic frameworks (XOFs) have been developed, constructing XOFs based on bromine(I) is desirable yet challenging due to the high sensitivity of bromine(I) species. In this work, we present the inaugural construction of stable bromine(I)‐bridged two‐dimensional (2D) halogen‐bonded organic frameworks, XOF(Br)−TPy−BF4/OTf, based on sensitive [N⋅⋅⋅Br⋅⋅⋅N]+ halogen bonds. The formation of XOF(Br)−TPy−BF4/OTf was monitored by 1H NMR, XPS, IR, SEM, TEM, HR‐TEM, SEAD. Their framework structures were established by the results from PXRD, theoretical simulations and SAXS. More importantly, XOF(Br) displayed excellent chemical and thermal stabilities. They exhibited stable two‐dimensional framework structures in various organic solvents and aqueous media, even over a wide pH range (pH 3–12), while the corresponding model compounds BrPy2BF4/OTf decomposed quickly even in the presence of minimal water. Furthermore, the influence of the counterions were investigated by replacing BF4 with OTf, which improved the stability of XOF(Br). This characteristic enabled XOF(Br) to serve as an efficient oxidizing reagent in aqueous environments, in contrast with the sensitivity of BrPy2BF4/OTf, which performed well only in organic media. This study not only deepens our fundamental understanding of organic frameworks but also opens new avenues for the development and application of multifunctional XOFs.

Halogen-Bonded Organic Frameworks (XOFs) Based on N⋅⋅⋅Br+⋅⋅⋅N Bonds: Robust Organic Networks Constructed by Fragile Bonds.

Organic frameworks face a trade-off between the framework stability and the bond dynamics, which necessitates the development of innovative linkages that can generate stable frameworks without hindering efficient synthesis. Although iodine(I)-based halogen-bonded organic frameworks (XOFs) have been developed, constructing XOFs based on bromine(I) is desirable yet challenging due to the high sensitivity of bromine(I) species. In this work, we present the inaugural construction of stable bromine(I)-bridged two-dimensional (2D) halogen-bonded organic frameworks, XOF(Br)-TPy-BF4/OTf, based on sensitive [N⋅⋅⋅Br⋅⋅⋅N]+ halogen bonds. The formation of XOF(Br)-TPy-BF4/OTf was monitored by 1H NMR, XPS, IR, SEM, TEM, HR-TEM, SEAD. Their framework structures were established by the results from PXRD, theoretical simulations and SAXS. More importantly, XOF(Br) displayed excellent chemical and thermal stabilities. They exhibited stable two-dimensional framework structures in various organic solvents and aqueous media, even over a wide pH range (pH 3-12), while the corresponding model compounds BrPy2BF4/OTf decomposed quickly even in the presence of minimal water. Furthermore, the influence of the counterions were investigated by replacing BF4 with OTf, which improved the stability of XOF(Br). This characteristic enabled XOF(Br) to serve as an efficient oxidizing reagent in aqueous environments, in contrast with the sensitivity of BrPy2BF4/OTf, which performed well only in organic media. This study not only deepens our fundamental understanding of organic frameworks but also opens new avenues for the development and application of multifunctional XOFs.

Nickel-Catalyzed Cyanation of Allylic Alcohols: High Degree of Chiral Inversion in Aqueous Reaction Media.

Nickel-catalyzed aqueous cyanation of allylic alcohols is herein described. This catalytic protocol provided environmentally friendly and operationally simple access to a variety of allylic nitriles in good yields. For chiral allylic alcohols, the reaction gave chiral allylic nitriles with a high degree of chiral inversion. The accelerated release of cyanide in H2O was crucial for the success of this reaction.

Exploring the Complex Chemistry and Degradation of Ascorbic Acid in Aqueous Nanoparticle Synthesis.

Ascorbic acid (AA) is the most widely used reductant for noble metal nanoparticle (NP) synthesis. Despite the synthetic relevance, its aqueous chemistry remains misunderstood, due in part to various assumptions about its reduction pathway which are insufficiently supported by experimental evidence. This study aims to provide an understanding of the complex chemistry associated with AA under aqueous conditions. We demonstrate that (i) AA undergoes appreciable degradation in alkaline solution on a timescale relevant to NP synthesis, (ii) contrary to popular belief, AA does not degrade into dehydroascorbic acid (DHA), nor is DHA the oxidized product of AA under noble metal NP synthetic conditions, (iii) DHA, which readily degrades under alkaline conditions, can also effectively reduce metal salt precursors to metal NPs, (iv) neither ascorbate nor dehydroascorbate act as surface capping agents post-synthetically on the NPs (v) AA degradation time greatly affects the morphology and polydispersity of the resultant NP. Results from our mechanistic investigation enabled us to utilize purposefully-aged reductants to achieve control over shape yield and monodispersity in the seed-mediated synthesis of Au nanorods. Our findings have important implications for achieving monodispersed products in the many metal NP synthesis reactions that make use of AA as a reducing agent.

Zinc Oxide Nanoparticles in the “Soil–Bacterial Community–Plant” System: Impact on the Stability of Soil Ecosystems

The use of man-made nanoparticles (NPs) has increased exponentially in recent years, many of which accumulate in significant quantities in soil, including through use in agriculture as nanofertilizers and nanopesticides. ZnO NPs are more environmentally friendly but have specific antimicrobial activity, which can affect soil microbiota, thereby influencing key microbial processes such as mineralization, nitrogen fixation and plant growth-promoting activities. Their behavior and persistence in soil depend on their chemical nature and soil characteristics. This review summarizes the applications of ZnO NPs in soil systems and their effects on various plants and soil microorganisms, particularly rhizobacteria that promote plant growth. A stimulating effect of ZnO NPs on the morphometric and biochemical characteristics of plants, as well as on soil microbiota and its activity at relatively low concentrations of up to 500 mg/mL and 250 mg/kg, respectively, is observed. As the concentration of ZnO NPs increases above these limits, toxic effects appear. The different effects of ZnO NPs are related to their size, dose, duration of exposure, solubility in water, as well as soil type, acidity and organic matter content. The review substantiates the need to study the behavior of ZnO NPs in the “soil-plant-microbiota” system for the possibility of using nanotechnologies in the agricultural industry and ensuring the safety of agricultural products.

Properties of a Dental Adhesive Containing Graphene and DOPA-Modified Graphene

Graphene is a promising biomaterial. However, its dispersion in aqueous medium is challenging. This study aimed to modify graphene nanoparticles with L-dopa to improve the properties of experimental dental adhesives. Adhesives were formulated with 0% (control), 0.25%, 0.5%, and 0.75% of graphene, modified or not. Particle modification and dispersion were microscopically assessed. Degree of conversion was tested by Fourier-transform infrared spectroscopy. Flexural strength and modulus of elasticity were evaluated by a 3-point flexural test. Bond strength was tested by shear. To test water sorption/solubility, samples were weighed during hydration and dehydration. Antibacterial activity was tested by Streptococcus mutans colony-forming units quantification. Cytotoxicity on fibroblasts was evaluated through a dentin barrier test. The modification of graphene improved the particle dispersion. Control presented the highest degree of conversion, flexural strength, and bond strength. In degree of conversion, 0.25% of groups were similar to control. In bond strength, groups of graphene modified by L-dopa were similar to Control. The modulus of elasticity was similar between groups. Cytotoxicity and water sorption/solubility decreased as particles increased. Compared to graphene, less graphene modified by L-dopa was needed to promote antibacterial activity. By modifying graphene with L-dopa, the properties of graphene and, therefore, the adhesives incorporated by it were enhanced.