ACS Omega最新文献

We investigated the site-disorder and thermal expansion of LnCa₄O(BO₃)₃ (Ln = Pr, Nd, Gd, Er, Tm) through a single crystal structural study conducted between 100 and 300 K. Additionally, a high-pressure synchrotron X-ray diffraction study at low temperatures was conducted to determine the compressibility of both ordered and disordered prototype oxyborate lanthanides, specifically NdCa₄O(BO₃)₃ and ErCa₄O(BO₃)₃. The study revealed distinct behaviors consistent with their respective ionic radii. Furthermore, satellite reflections at 50 K, along with the onset of a triple a-parameter in the Nd crystal, indicate that the ground state of this extensively studied family may be different from what was previously reported.

The optimal design of cement slurry by balancing various cement additives and cement is critical for effective oil well cementation job. However, given adverse circumstances of application, existing additives may not be sufficient to perform suitably in challenging conditions, leading to premature cement hydration, formation of microcracks, and gas channeling pathways. Thus, this study explores the use of a single-step silica nanofluid (NP size: 5–10, 90–100, and 250–300 nm and concentration: 1, 3, and 5 wt %) as an additive and explores its effect on thickening time, fluid loss, and rheological behavior of class G cement slurry at high-pressure and high-temperature (HPHT) conditions (135 °C and 3625 psi). The improvement in thickening time, fluid loss, and rheology of conventional slurry was greater for low NP size than the nanofluid of high NP size: the nanofluid size, e.g., 5–10 nm, and concentration (1 wt %) were found to accelerate the thickening time by 30–40% while reducing fluid loss from 38 mL (no silica, slurry CS) to 30 mL (with silica, slurry C1). The rheological behavior was studied via shear (viscosity) and dynamic (elastic moduli, G′) modes to evaluate the viscosity, hysteresis, and elastic response of slurry with and without nanofluid. The inclusion of nanofluid slightly reduced the slurry viscosity; however, all slurries exhibited shear thinning with superior fitting with the power law model. As compared to slurry CS, hysteresis of slurry C1 was least dependent on shear deformation, and thus, it showed that it almost matched viscosity profiles during loading and unloading cycles. The addition of silica was found to maintain the original properties of cement slurry, establishing that cement had not agglomerated, and no sedimentation was observed even at shear rates of 1000 s^–1. The results of this study greatly promote the use of silica nanofluid as an important additive in class G cement for cementation operations, which is unlikely with a two-step nanofluid where nanoparticles are expensive, and upon mixing, they tend to agglomerate and make large size clusters.

Photothermal conversion efficiency (η) plays a crucial role in selecting suitable gold nanoparticles for photothermal therapeutic applications. The photothermal efficiency depends on the material used for the nanoparticles as well as their various parameters, such as size and shape. By maximizing the light-to-heat conversion efficiency (η), one can reduce the concentration of nanoparticle drugs for photothermal cancer treatment and apply lower laser power to irradiate the tumor. In our study, we explored a new hybrid plasmonic conjugate for theranostic (therapy + diagnostic) applications. We conjugated PEG-functionalized 20 nm gold nanospheres with cyanine IR dyes via a PEG linker. The resulting conjugates exhibited significantly enhanced photothermal properties compared with bare nanoparticles. We experimentally showed that a proposed new hybrid plasmonic conjugate can achieve almost four times larger conversion efficiency (47.7%) than 20 nm gold nanospheres (12%). The enhanced photothermal properties of these gold conjugates can provide the required temperature for the photothermal treatment of cancer cells with lower concentrations of gold nanoparticles injected in the body as well as with lower applied incident laser power density. Moreover, the improved photothermal properties of the conjugates can be explained by a synergistic effect that has not been observed in the past. This effect results from the coupling between the metal nanosphere and the organic dye.

Pancreatic ductal adenocarcinoma (PDAC) is one among the most lethal malignancies due to its aggressive behavior and resistance to conventional therapies. Hypoxia significantly contributes to cancer progression and therapeutic resistance of PDAC. microRNAs (miRNAs/miRs) have emerged as critical regulators of various biological processes. miR-210 is known as the “hypoxamir” due to its prominent role in cellular responses to hypoxia. In this study, we investigated the multifaceted role of miR-210 in PDAC using miR-210 knockout (KO) cellular models to elucidate its functions under hypoxic conditions. Hypoxia-inducible factor-1α (HIF1-α), a key transcription factor activated in response to low oxygen levels, upregulates miR-210. miR-210 maintains cancer stem cell (CSC) phenotypes and promotes epithelial–mesenchymal transition (EMT), which is essential for tumor initiation, metastasis, and therapeutic resistance. Our findings demonstrate that miR-210 regulates the expression of CSC markers, such as CD24, CD44, and CD133, and EMT markers, including E-cadherin, Vimentin, and Snail. Specifically, depletion of miR-210 reversed EMT and CSC marker expression levels in hypoxic Panc-1 and MiaPaCa-2 PDAC cells. These regulatory actions facilitate a more invasive and treatment-resistant PDAC phenotype. Understanding the regulatory network involving miR-210 under hypoxic conditions may reveal new therapeutic targets for combating PDAC and improving patient outcomes. Our data suggest that miR-210 is a critical regulator of HIF1-α expression, EMT, and the stemness of PDAC cells in hypoxic environments.

A mild and general method for photoredox-catalyzed trifluoromethylative and pentafluoroethylative heterofunctionalization of alkenes is proposed. In this reaction, the Togni reagent serves as a CF₃- or CF₂CF₃-radical source for the regioselective formation of the C–CF₃ and C–CF₂CF₃ bonds from alkenes, and additional nucleophiles (O, S, N) provide C–O, C–S, and C–N bonds, respectively. These reactions provide a common gateway to access the fluoroalkylative heterofunctionalization of alkenes.

This experimental study reports the thermodynamic influence of three different amino acids on methane hydrate in oil-dominated systems, namely, glycine, proline, and alanine. To thoroughly examine the effect of selected amino acids on methane (CH₄) hydrate formation compared to the commercial inhibitor monoethylene glycol (MEG) in the presence of oil, the hydrate liquid–vapor equilibrium (H-Lw-Lo-V) curve is used to measure amino acid aqueous solutions. All experiments are performed at a concentration of 10 wt % by using the isochoric T-cycle technique in a high-pressure reactor cell at the selected range of pressures with temperatures of 4.0–9.0 MPa and 276.5–286.0 K, respectively. Results show that all studied amino acids inhibit hydrate formation of methane; the inhibition trend shows as glycine > alanine > proline in both systems; in the brine water system, the inhibition performance was higher than in the pure water system due to the presence of NaCl. Glycine showed the highest inhibition strength in both systems with an average reduced temperature in pure and brine water of 0.92 and 1.75 K, respectively, at 10 wt %, making the inhibition performance of glycine comparable to the commercial inhibitor MEG. The inhibition effect is attributed to the amino acid’s hydrogen bonding energies and side group alkyl chain. Calculating the dissociation enthalpies of methane hydrates in the presence of amino acids using the Clausius–Clapeyron equation implies that the amino acids do not occupy the cage structures during methane hydrate formation.

Salinity inhibits the uptake of nitrogen, which slows down the growth and prevents plant reproduction. Certain ions, especially chloride, are poisonous to plants; when their concentration increases, the plant becomes poisoned and eventually perishes. The adaptability of several table beet cultivars (Beta vulgaris L.) to saline water irrigation creates new opportunities for extending beet production, increases the added economic value, and has a positive environmental impact. A pot experiment is carried out for two successive seasons, 2019/2020 and 2020/2021, to investigate the effect of irrigation with agriculture saline drainage water on the growth and biochemical traits of three selected cultivars (Detroit Dark Red, Red Ball, and Red Ace). Four levels of salinity are applied (1000, 2000, 3000, and 4000 ppm) along with tap water of 260 ppm salinity, which serves as the control. Detroit Dark Red beets show the best results among the other cultivars under consideration. Irrigation with the first level of saline water (1000 ppm) at both seasons of cultivation results in a significant increase rate in growth parameters (13–23%). The second level of salinity (2000 ppm) shows the maximum increase rate of some chemical constituents, such as ascorbic acid (16.26%), nitrogen (58.21%), phosphorus (11.94%), potassium (34.66%), and sodium (85.14%). The levels of total soluble solids (TSS), anthocyanins, proline, total sugars, water saturation deficit, and sodium increase significantly in proportion to saline water concentrations. The selected table beet mature leaves show slight variations in anatomical structure, especially in the B. vulgaris L. cv. Detroit Dark Red under the highest salinity concentration (4000 ppm) was less than that of the control and the other two cultivars. Other cultivars may be the subject in the near future to study the effect of their salinity tolerance with the aim of increasing productivity, enhancing their characteristics, and preserving the environment.

Contamination of water by oil-based pollutants is a major environmental problem because of its harmful impact on human life, marine life, and the environment. As a result, a wide range of materials are being investigated for the effective separation of oil from water. Among these materials, metal–organic frameworks (MOFs) and their composites have emerged as excellent candidates due to their ultraporous structures with high surface areas that can be engineered to achieve high selectivity for one of the phases in an oil/water mixture for efficient water filtration. However, the often nanocrystalline/microcrystalline form of MOFs combined with challenges of processability and poor stability in water has largely limited their use in industrial and environmental applications. Hence, considerable efforts have recently been made to improve the performance and stability of MOFs by introducing hydrophobic functional groups into the organic linkers and fabricating polymer-MOF composites to increase their stability and recyclability. In addition, the use of biobased or biodegradable MOF composites can be particularly useful for applications in natural environments. This Review presents recent advances in the field of hydrophobic MOFs and MOF-based composites studied for the separation of oil from oil/water mixtures, with an account of future challenges in this area.

Silver nanoparticles (AgNPs) are excellent antimicrobial agents and promising candidates for preventing or treating bacterial infections caused by antibiotic resistant strains. However, their increasing use in commercial products raises concerns about their environmental impact. In addition, traditional physicochemical approaches often involve harmful agents and excessive energy consumption, resulting in AgNPs with short-term colloidal stability and silver ion leaching. To address these issues, we designed stable hybrid lignin–silver nanoparticles (AgLigNPs) intended to effectively hit bacterial envelopes as a main antimicrobial target. The lignin nanoparticles (LigNPs), serving as a reducing and stabilizing agent for AgNPs, have a median size of 256 nm and a circularity of 0.985. These LigNPs were prepared using the dialysis solvent exchange method, producing spherical particles stable under alkaline conditions and featuring reducing groups oriented toward a wrinkled surface, facilitating AgNPs synthesis and attachment. Maximum accumulation of silver on the LigNP surface was observed at a mass reaction ratio m_Ag:m_Lig of 0.25, at pH 11. The AgLigNPs completely inhibited suspension growth and reduced biofilm development by 50% in three tested strains of Pseudomonas aeruginosa at a concentration of 80/9.5 (lignin/silver) mg L^–1. Compared to unattached AgNPs, AgLigNPs required two to eight times lower silver concentrations to achieve complete inhibition. Additionally, our silver-containing nanosystems were effective against bacteria at safe concentrations in HEK-293 and HaCaT tissue cultures. Stability experiments revealed that the nanosystems tend to aggregate in media used for bacterial cell cultures but remain stable in media used for tissue cultures. In all tested media, the nanoparticles retained their integrity, and the presence of lignin facilitated the prevention of silver ions from leaching. Overall, our data demonstrate the suitability of AgLigNPs for further valorization in the biomedical sector.

During the transportation of hydrogen-doped natural gas (HCNG), there is a risk of uneven distribution of hydrogen at the elbow, causing hydrogen damage to the pipeline. Therefore, based on the basic principles of computational fluid dynamics, this paper uses a hybrid model to describe the flow process of HCNG in an elbow. The results show that under normal transportation, the hydrogen volume fraction varies within 0.2% with the influence of pressure, flow velocity, temperature, hydrogen volume fraction, and undulating angle, and the uneven distribution of hydrogen in the elbow can be ignored. However, in the shutdown state, the hydrogen slip rate gradually slows down, the hydrogen volume fraction is distributed in a horizontal concentration gradient along the vertical direction, and it gradually accumulates at the height of the undulating tube. The difference in hydrogen volume fraction reaches 50%, and the stratification phenomenon is obvious.