ACS Omega最新文献

Our aim was to establish an effective method for protein extraction from freshly frozen human peripheral nerves, determine the minimum amount required for consistent protein extraction outcomes, and assess which method produced the highest number of protein identities. Five extraction methods were compared using 8 M urea and Ripa buffer using either the Bullet Blender or Bioruptor. Out of the total 2619 identified proteins, protein extraction using the Ripa buffer combined with either Bioruptor or Bullet Blender resulted in the identification of 1582 (60%) and 1615 (62%) proteins, respectively. In contrast, using 8 M urea and Bioruptor for protein extraction resulted in 1022 proteins (39%), whereas employing Bullet Blender yielded 1446 proteins (55%). Sample amounts, ranging from 0.6 to 10 mg, were prepared with consistent protein extraction outcome obtained for samples ≥1.2 mg. Combining Ripa and 8 M urea with Bullet Blender increased protein identification to 2126 (81%). Proteins were classified by their cell components, molecular functions, and biological processes. Furthermore, a subclassification of proteins involved in the extracellular matrix (ECM) was introduced. We recommend the use of Ripa buffer, in combination with 8 M urea and Bullet Blender for extracting proteins from fresh-frozen human nerves weighing ≥1.2 mg.

This study investigates the characteristics of the wax precipitation activity in the condensates. The patterns of wax precipitation are elucidated by analyzing the composition and amount of precipitate produced at various temperatures, verifying the influence mechanism of factors such as condensate composition and temperature on wax separation. The findings reveal that a decrease in the temperature enhances the contact of wax molecules by reducing their thermal motion, leading to wax particle precipitation. This also weakens the Brownian motion of precipitated wax, further promoting their aggregation and subsequent deposition. Consequently, the amount of wax precipitate increased as the temperature drops. Moreover, an increase in asphaltenes and resins in the condensates raises the critical crystalline radius of wax, making wax precipitation more difficult. Therefore, the amount of wax precipitate decreases as the concentration of asphaltenes and resins in the condensates increases. Additionally, because the solubilities of different hydrocarbon components change at different rates with decreasing temperature, lower carbon number hydrocarbons precipitate more actively in the early stages, with their precipitation rate declining as their concentration in the system diminishes. This relatively increases the precipitation rate of higher carbon number hydrocarbons in the later stage, increasing the proportion of high carbon number components in the composition curve of the wax deposit as the temperature decreases. Finally, the four components of the system─saturated hydrocarbons, aromatic hydrocarbons, asphaltenes, and resins─exhibit different precipitation behaviors as the temperature decreases, and their precipitation proportions show different trends at various temperatures. This study provides data to enrich the theoretical understanding of wax precipitation mechanisms in condensates under well-bore environmental conditions. It can support the development of effective wax blockage prevention strategies in reservoir development.

The chemical, structural, and morphological diversity of birnessite, a 2D layered MnO₂, has opened avenues for its application as an electrocatalyst toward both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Among pristine birnessites prepared by different methods, the freestanding flakes (primary structure) obtained from molten salt (MS-KMnO) showed remarkable bifunctional activity as compared to samples with thicker plates or a hierarchical honeycomb-like (type-I secondary structure) morphology. While the ORR onset potential (E_onset) and halfwave potential (E_1/2) for MS-KMnO were recorded at 0.89 and 0.81 V vs RHE, respectively, the OER overpotential (η) was found to be 300 mV. We demonstrated heat-induced secondary structure evolution by modification of the molten salt method, which led to a decrease in activity. In contrast to previous studies, the Co-doped birnessite (Co-KMnO) prepared in molten salt showed lower bifunctional activity (ORR, E_1/2 = 0.72 V; OER, η= 460 mV) as compared to MS-KMnO. Co-KMnO showed an interwoven wrinkled sheet-like (type-II secondary structure) morphology, with Co³⁺ present in both the in-layer and the interlayer. However, in Co-KMnO/360 prepared at a lower reaction temperature, the areal coverage of the type-II structure reduces, leading to an increase in ORR (E_1/2 = 0.76 V) and OER (η = 440 mV) activity. The chronopotentiometry for 100 h at a constant OER current of 50 mA cm^–2 showed an increase in potential from 1.62 to 1.89 V and the characterization of the sample post-treatment showed degradation of the layered structure in MS-KMnO. The samples obtained after 1000 CV cycles in both the ORR and the OER regions showed the formation of secondary structures with a substantial decrease in the Mn³⁺/Mn⁴⁺ ratio. This study demonstrates that morphology tuning within the 2D birnessite system has a marked effect on its bifunctional activity.

Shale reservoirs, often acting as caprocks for conventional hydrocarbon reservoirs, exhibit moderate to high porosity and remarkably low permeability. Organic-rich shales serve as reservoirs for unconventional hydrocarbons. This study focused on evaluating the characteristics of the source rocks and the factors influencing pore parameters in organic-rich shale from a Permian Basin in India, exploring its feasibility as both a CO₂ sink and a natural gas source. Experimental techniques were employed to explore the mineral and the organic matter characteristics along with attributes of the pores hosted within them. The investigated shales displayed diverse thermal maturity levels, spanning from that in oil-prone to gas-prone zones, with the total organic carbon content varying from 0.72 to 24.98 wt %, indicating substantial organic richness. Rock-Eval pyrolysis results revealed a range of thermal maturity (T_max) values between 426 and 474 °C, while X-ray diffraction analysis indicated significant quantities of illite and kaolinite, along with trace amounts of pyrite in certain samples. Field-emission scanning electron microscopy imaging and its detailed interpretation provided valuable insights into the pore structure and arrangement. In our study, we found that both the clay content and the organic matter significantly contribute to gas adsorption. While clay content strongly influences mesopore attributes, the organic matter predominantly affects micropore attributes. Furthermore, a direct relationship among fractal dimension, surface area, and pore volume, indicating increased complexities with these variables. Our examination of mesopore fractal attributes revealed that smaller mesopores exhibit a more convoluted and irregular configuration in comparison to the larger ones. These findings provide significant insights into the pore morphology of the analyzed shale sample.

The photoexcitation of aqueous iodide solutions is a prototype for the generation of electrons in liquid water. Upon one-photon excitation, the precursors of the solvated electrons are localized states with a radius of a few angstroms. In contrast, with the aid of transient absorption spectroscopy at terahertz, near-infrared, and visible frequencies, we show that the two-photon absorption of ∼400 nm pulses can impulsively generate short-lived (∼250 fs), delocalized electrons that are released tens of angstroms away from the parent ion. We propose that these states can be ascribed to 5p → 6p transitions that, in turn, could be thought of as frustrated Rydberg orbitals or large radius excitons. By capitalizing on the unique capabilities of transient terahertz spectroscopy, we estimate that these delocalized states are characterized by an electronic mobility and diffusivity that are about 500 times greater than those of the fully relaxed electrons.

There is growing interest in generating micro- or nanobubbles for enhancing aeration. Small bubbles not only enhance the interfacial area for gas–liquid mass transfer but also may enhance the equilibrium solubility if the size of the bubbles is small enough. In this note, we demonstrate the use of a vortex-based hydrodynamic cavitation device (VD) for generating small bubbles and enhancing aeration. Experimental results for conventional aeration and aeration with VD operated under three different conditions are presented. A reference case of potential degassing because of the low pressure generated in the cavitation device was also investigated. Experiments were carried out in a bubble column using DI water as the liquid phase. The dissolved oxygen (DO) concentration was measured using a precalibrated dissolved oxygen probe. Measurements of transient profiles of dissolved gas concentrations were carried out under different operating conditions. A generalized framework to analyze mass transfer in the presence of degassing, absorption, and desorption (via top surface or large bubbles) is developed and used for interpreting the experimental data. The per-pass degassing factor of VD was found to increase with the power dissipation [∝ (P–P_c)^0.4, where P is power dissipation and P_c is the critical power beyond which degassing starts]. The aeration generated by VD was found to realize 30% higher DO concentration beyond the equilibrium solubility at atmospheric conditions. The bubble sizes estimated from the steady-state DO concentration were in the range from 80 to 200 μm for the operating parameters considered in this work. The presented results demonstrate the effectiveness of VD for enhancing aeration and will be useful for intensifying gas–liquid processes.

Metal oxides (MOs) are the key materials in applications of biomedicine industrial technologies due to their versatile features. Knowing their possible toxicity level is crucial given some specific environments, particularly in water. We have learned that their reactivity almost depends on the electronic structure on the surface of the MOs. Thus, a detailed understanding of the electronic structure on the surface and its reactivity processes is useful for determining the toxicity in MOs and defining good descriptive parameters. We simulated the interaction of ZnO and TiO₂ slab models with water and checked their geometric and electronic structure changes from the bulk of the material to the water interface. To this end, we used the density functional tight binding theory coupled with finite temperature molecular dynamics. We have observed the interaction of water with the MO surface in terms of electronic and geometric parameters for several conditions, such as temperature, hydrogenated or clean, and exposed surface. In doing so, we provide molecular-level insights into topographical and electronic processes on MO surfaces besides finding critical points on the surface that can explain the initialization of dissolution processes. Thus, we reveal information about potential toxicity descriptors in a systematic analysis approach.

In the past decade, liquid chromatography–mass spectrometry (LC-MS/MS) has become pivotal in clinical diagnosis, drug discovery, and bioanalytical science due to its high sensitivity and rapid analysis. We have developed an ultrasensitive and robust LC-MS/MS method for the simultaneous detection and quantification of cyclosporine A (CsA) and urolithin A (UA) employing ascomycin (ASC) and naringenin (NAR) as internal standards (ISTDs). The method was validated for clinical use, revealing interspecies differences between human plasma and other mammals (e.g., mouse, rat, feline, canine, and bovine serum). Validation parameters, including accuracy, precision, limits of quantification, specificity, selectivity, carryover, linearity, stability, and recovery, met acceptable ICH standards. Linear regression across the full calibration range (1–250 ng/mL for CsA and 0.5–125 ng/mL for UA) yielded an average R² ≥ 0.999 in all mammal models. The method achieved a limit of quantification (LOQ) of 1–2.5 ng/mL across all model plasma samples with negligible carryover and demonstrated sample stability up to 96 h intra- and interday and 48 h for bovine serum. The method was successfully applied to quantify CsA and UA in canine samples following oral administration from a previous study. With a rapid run time of 6 min, this method offers high selectivity and precision, making it ideal for analyzing limited sample sizes and addressing regulatory challenges. The ability to simultaneously quantify CsA and UA has significant clinical potential for managing complex immuno-inflammatory diseases, enabling precise dose adjustments, and optimizing treatment outcomes.

Salvianolic acid A (SAA) has an important application value for preventing and treating cardiovascular diseases. In this study, we developed a novel multienzyme cascade system for the efficient biosynthesis of SAA, utilizing l-tyrosine (l-Tyr) as a cost-effective and stable starting material. The cascade system incorporated four enzymes: membrane-bound l-amino acid deaminase from Proteus vulgaris (Pvml-AAD), d-lactate dehydrogenase from Pediococcus acidilactici (Pad-LDH), 4-hydroxyphenylacetate 3-hydroxylase from Escherichia coli (EcHpaBC), and formate dehydrogenase from Mycobacterium vaccae N10 (MvFDH). All reaction steps in the cascade system were thermodynamically favorable. In addition, to avoid generating an unstable intermediate (3,4-dihydroxyphenyl-pyruvate, DHPPA), which was produced owing to the promiscuity of EcHpaBC and Pad-LDH, we performed the cascade system according to the reaction sequence of deamination, chiral reduction, and ortho-hydroxylation. Under optimized conditions, the developed cascade system yielded 81.67 mM SAA from an initial concentration of 100 mM l-Tyr, corresponding to a yield of 81.67%.

Niemann-Pick type C (NPC) is a lysosomal storage disorder that will cause eventual brain damage with limited treatment options available. Though clinical trials are undergoing with repurposed pharmaceuticals, no novel chemotype exists purely for the treatment of NPC. In 2021, an azasterol was found to bind to both NPC1 and NPC2 proteins and is considered as a cholesterol mimic. A convergent synthesis to obtain a hydroxy-15-azasterol was completed in 12 steps, from 2-oxepanone.