ACS Omega最新文献

Interpreting spectral data to analyze the structure and properties of unknown chemicals requires a lot of time and effort. Herein, we developed a machine-learning model that simultaneously trains on multiple spectroscopic data to identify functional groups of compounds more accurately and quickly. An artificial neural network model trained on Fourier-transform infrared, proton nuclear magnetic resonance, and ¹³C nuclear magnetic resonance together identified 17 functional groups with a macro-average F1 score of 0.93, outperforming the model using a single type of spectroscopy. The results indicated that training a machine-learning model with multiple spectral data can provide more accurate structural analysis when analyzing the structure of unknown chemicals, as can using multiple spectroscopy methods simultaneously.

Coal-bed methane development is closely related to the pore-fracture characteristics and permeability of the coal reservoirs. After the primary structured coal is damaged and deformed, its pore-fracture system changes, which affects the permeability of the coal reservoir. To investigate the pore-fracture characteristics of deep coal with different coal-body structures and its impact on permeability, the coal seams of the Longtan formation in the Changning block of southern Sichuan were taken as the research object. A systematic study was conducted based on high-pressure mercury intrusion porosimetry, scanning electron microscopy, and full stress–strain permeability experiments. The results indicate that the pore connectivity of primary structured coal is superior to that of fragmented structured coal. Tectonic stress can modify the structure of the seepage pores and fractures in coal samples. The permeability of coal seams containing fractures is higher than that of intact coal seams after stress-induced transformation, suggesting that brittle tectonic deformation facilitates the modification of seepage pores and microfractures, which is more conducive to the development of coalbed methane. Modification of pores and fractures by strain-induced damage in coal seams under stress is the underlying cause of permeability changes in coal seams.

Hydrolyzed keratin (HK) refers to any hydrolysate of keratin of a different origin derived by acid, alkali, enzymatic, or other methods of hydrolysis. HK is water soluble and has distinct chemical–physical properties compared to fibrous keratin. Although HK is employed across various technological sectors, there is a notable gap in the literature regarding the detailed chemical–physical properties of commercially available HKs. This study aims to address this gap by providing a thorough analysis of the surface-active, emulsifying, and thickening properties of three commercially available HKs. The results reveal relevant differences among HKs marketed under the International Nomenclature Cosmetic Ingredient (INCI) name “Hydrolyzed Keratin,” with variations in their chemical–physical properties, primarily influenced by molecular weight. Specifically, HKs with a higher average M_w (>3000 Da) and protein content demonstrate enhanced emulsifying and thickening capabilities. Conversely, HKs with low M_w (<1000 Da) do not show surface-active properties suitable for the preparation of emulsions. Therefore, this study underscores the need for the standardization of commercially available HK products to obtain biomaterials with tailored and specific chemical–physical properties, enhancing their potential applications in cosmetic and pharmaceutical topical formulations.

The safe exploitation and transportation of hydrates are seriously threatened by hydrate growth and deposition in the flow channel. However, silt impurities are inevitably present in the exploitation flow channels. This article aims to clarify how slit impurities affect hydrate growth, deposition, and mechanical properties. The process of hydrate growth and deposition in the presence of silty sand on the pipe walls of different solution systems and pipe wall materials was investigated. The results indicated that, in the deionized water system for both metallic pipe wall and nonmetallic pipe wall, and in the sodium dodecyl sulfate (SDS) solution system for metallic pipe wall, the hydrate growth rate increased by 131.48, 114.76, and 84.89%, respectively, after adding a 9.0% volume fraction of silty sand. Additionally, the adhesion strength between the hydrate and pipe wall at different silty sand contents was measured. It was found that the adhesion strength ranged from 140.61 to 234.64 kPa. With an increase in the silty sand content, the adhesion strength first increased and then decreased, reaching a maximum when the silty sand volume fraction was 3%. With the extension of the hydrate formation time, the adhesion strength increased by up to 57.62%. Furthermore, the mechanism of hydrate growth in the presence of silty sand was proposed. The hydrate growth in the SDS solution system differed from that in the deionized water system. In the presence of SDS, no dendritic hydrate was observed around the generated hydrate, while dendritic hydrates were observed around the hydrates in the deionized water systems with different pipe wall materials, with more dendritic hydrates forming in the metallic pipe wall. After addition of silty sand, the initial position of hydrate formation shifted from the interior of the droplet to the silty sand inside the droplet. This work provided data support for preventing hydrate plugging in the flow channel and was of great significance for ensuring the safe production of hydrates.

It is now widely accepted that detailed knowledge of the physicochemical characteristics of the β-hematin crystals, i.e., the synthetic versions of the natural hemozoin crystals, is important for understanding their formation, the design of antimalarial medicines, and malarial diagnosis. We report that the overall physical properties exhibited by β-hematins greatly depend on the synthetic media. Here, we synthesize β-hematin from hemin in aqueous-acetate and in aqueous-oily media and characterize their properties by several techniques. Infrared spectra clearly demonstrate the formation of β-hematin in both media. The β-hematin crystals prepared in aqueous-acetate are composed by needle-like particles with average lengths around 760–770 nm; their lattice parameters and unit cell volumes are larger than those reported in the literature. They are paramagnetic at 300 K and antiferromagnetic at very low temperatures. Their Mössbauer spectra at 298 K, 77 K, and 10 K are consistent with the presence of high-spin Fe (III) and are less asymmetric as a result of the occurrence of fast spin–spin relaxation time, and their surface composition is complex, showing the presence of a multiplicity of iron oxidation and spin states (although with a majority of high-spin Fe³⁺ ions). In comparison, the β-hematin crystals prepared in aqueous-oily medium have significantly smaller lengths (ca. 560 nm) and slightly larger unit cell volume in comparison to the previous sample. The magnetic measurements show that they are affected by superparamagnetism and paramagnetism at 298 K and the coexistence of weakly ferromagnetic or possibly ferrimagnetic and paramagnetic phases at 80 K. Their Mössbauer spectra at 298 K, 77 K, and 10 K, also consistent with the presence of high-spin Fe (III), show longer spin–spin relaxation times, and their surface composition is also complex containing less surface OH^– groups and higher amounts of Fe (II) ions in low- and high-spin states. The observed differences are discussed in relation to the specific formation conditions present in the synthesis medium. The results reported here are of outmost importance for understanding how the physicochemical properties of β-hematins depend on the synthesis conditions.

Pyrolysis technology is a promising way to convert sludge to char, tar, and gas. As the ash content in sludge can reach more than half, the influence of metals (alkali and alkaline earth metals, Fe) on the pyrolysis process and tar distribution was studied by comparing the raw sludge, stepwise pickling sludge, and metal-loaded sludge pyrolysis. The results show that the maximum weight loss rate temperature of the sludge moved to the high-temperature zone, from 270 °C (raw sludge) to 299–338 °C (pickling sludge). The activation energy also increased after pickling. The presence of metals has a catalytic effect on the thermal decomposition of the sludge. Moreover, the total amount of the tar is increased by 32.47%, 138.41%, and 240.59% for pickling sludge treated with different acids (HCl, HF, and HCl + HF, respectively). The cracking performance of metals on tar is related to their type and loading amount. Fe exhibits a strong cracking ability for sludge volatiles, although its loading content is the lowest. Mg reduces the total amount of tar by 71.89%. Also, the cracking rate of aliphatic and aromatics is lower than that of oxygen-containing compounds under the action of the same metals. Metals can crack the oxygen-containing compounds, aromatics, and aliphatics into smaller ones through deoxygenation or the cracking of an aliphatic side chain. Among them, Na has the ability to promote the formation of alcohols by reacting with oxygen-containing functional groups, such as hydroxyl and carbonyl, in compounds. Meanwhile, K, Ca, Mg, and Fe can cause alcohols to undergo cracking and transform into small molecular compounds. Metals in sludge play a crucial role in the formation of tar during pyrolysis.

Human La-related protein 6 (HsLARP6) regulates the highly organized biosynthesis of type I procollagen polypeptides and affects the proper assembly of procollagen peptides into heterotrimers of type I procollagen. HsLARP6-mediated regulation of collagen biosynthesis is mediated through interaction with the 5′ stem loop (5′SL) motif found in type I and III collagen mRNA. Recent studies highlight the involvement of HsLARP6 in fibroproliferative diseases and its potential as a target for therapeutic intervention. The intrinsic propensity of the La domain of HsLARP6 to aggregate hampers studies probing the molecular basis of biologically and disease-relevant structure–function relationships, particularly when high concentrations are required. This work provides detailed procedures to produce milligram amounts of RNase-free and functional La domain of HsLARP6. Furthermore, we investigated the effects of the protein construct length and RNA binding on protein stability. C-terminal truncations greatly impact protein stability, while N-terminal truncations have little to no effect on protein aggregation and RNA binding. When in complex with its cognate 5′SL RNA, the La domain shows unprecedented stability compared to the aggregation-prone unbound state. The protein-RNA complex remains stable for at least 50 times longer than the unbound state under identical conditions. These results provide a significant platform for further studies of the molecular recognition of 5′SL by HsLARP6.

Pyrrolic units have been utilized as building blocks for organic semiconducting small molecules and polymers in the recent past. Even though pyrrole-based materials have shown promising semiconducting properties, they have been challenging due to their lower stability under ambient conditions. In this study, we synthesized two pyrrole-fused moieties: 1H-indole (IN) and pyrrolo[2,3-b] pyridine (PPy), which were then explored for their potential as effective donor moieties in organic semiconducting materials. Each donor block was employed to synthesize two donor–acceptor–donor-type small molecules. Thiophene-flanked benzo[c][1,2,5]thiadiazole was used as an acceptor to generate diethyl 6,6’-(benzo[c][1,2,5]thiadiazole-4,7-diylbis(thiophene-5,2-diyl))bis(1-dodecyl-1H-indole-2-carboxylate (IN-BT2T-IN) and diethyl 6,6’-(benzo[c][1,2,5]thiadiazole-4,7-diylbis(thiophene-5,2-diyl))bis(1-dodecyl-1H-pyrrolo[2,3-b]pyridine-2-carboxylate (PPy-BT2T-PPy) donor–acceptor–donor molecules. These novel donor–acceptor–donor molecules were tested for their hole-transport properties by fabricating and testing organic field-effect transistors (OFETs). Both molecules exhibited moderate hole-transporting properties with maximum hole mobilities of 0.00483 and 0.00381 cm² V^–1 s^–1 for IN-BT2T-IN and PPy-BT2T-PPy, measured under annealing conditions. The enhanced hole mobilities measured in the annealed OFET devices were attributed to thermally induced crystallinity, as demonstrated by atomic force microscopy and grazing incidence X-ray diffraction measurements.

Biobased closed-loop recyclable olefin-like materials are environmentally friendly and have promising application prospects. However, such materials are scarce, and especially the olefin-like materials developed so far are limited to polyester materials. Therefore, developing nonpolyester biobased olefin-like materials is of significant interest. In this study, a castor oil-based poly(ester amide) (PEA) with polyethylene-like properties and closed-loop recyclability was successfully prepared. The obtained PEA materials exhibit thermal and mechanical properties comparable to polyethylene and surpass those of previously reported linear poly(ester amide)s. Notably, PEA can be completely hydrolyzed to its precursors, N¹,N¹⁰-bis(3-hydroxypropyl) decanediamide (DSE) and sebacic acid (SA), with yields of 73.1–75.8 and 92.8–96.2%, respectively. Further experiments demonstrated that repolymerization of recovered DSE and SA produced REPEA materials with mechanical properties equivalent to the original polymer. This study achieves closed-loop recycling for biobased linear nonpolyester materials, which offers a novel approach to design olefin-like sustainable materials.

Phosphors of Bi₄Ge₃O₁₂:Eu³⁺ were obtained by using the polymeric precursor route. After confirming the Eu incorporated into the Bi₄Ge₃O₁₂ lattice, we analyzed the magnetic behavior in the systems with 0%, 2%, 5%, and 10%. The magnetization vs magnetic field measurements evidenced ferromagnetism in all the samples, with different magnetization saturation values. In the pristine structure, the magnetic behavior is directly related to Bi vacancies, where the neighbor O atoms induce spin polarization. The ferromagnetic characteristics are enhanced in the 2% Eu content because Eu atoms take on the Bi vacancy sites. In contrast, the ferromagnetic character diminishes as the Eu content is increased to 5%, which is directly correlated with site competence as Eu can occupy either Bi or Ge sites. Upon raising the Eu percentage to 10%, the ferromagnetic character gets strengthened. In this case, we hypothesize that zones of the material with a high concentration of Eu may appear with ferromagnetic alignment, confirmed by our ab initio computations. The evidence generated in this paper lays the foundations for considering rare-earth-doped Bi₄Ge₃O₁₂ for applications in the spintronics industry.