Arabian Journal of Chemistry最新文献

A novel fire-preventing composite gel, mainly made from steel slag (SS) and silica fume (SF), was created for a coal mine’s spontaneous combustion. The gelation mechanism of the steel slag-based composite gel (SSG) was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (SEM). The findings suggest that SSG is generated through the processes of hydration and geopolymerization involving SS and SF. And in the alkaline milieu of a 1.5 M water glass solution, SSG manifests enhanced strength and water retention capacities. Moreover, the fire prevention and extinguishing performance of the SSG was analyzed and verified using low-temperature oxidation, thermogravimetry, and low temperature nitrogen adsorption experiment (LTNA). The SSG has proven highly effective in suppressing spontaneous coal combustion by inhibiting CO production, raising the coal oxidation temperature, and reducing the contact area between oxygen and the coal body.

Background

Schisandra chinensis (Turcz.) Baill (Schisandraceae) and Acorus tatarinowii Schott (Araceae Juss) (Sc-At) are two traditional Chinese medicinal herbs that are widely used in the treatment of neurological disorders such as insomnia. In our previous study, we found that Sc-At could improve the therapeutic efficacy of Alzheimer’s disease by affecting aromatase activity and estrogen levels, among other pathways.

Material and methods

In this study, first, the ameliorative effect of Sc-At on cognitive dysfunction in Alzheimer’s disease model rats was verified by Y-maze test together with Elisa assay. Second, fecal untargeted metabolomics analysis was performed using a UPLC-Q-TOF/MS-based metabolomics approach. 16S rDNA sequencing was utilized to screen the differential flora between groups, and linear discriminantan alysis effect size (LEfSe) was used to find the target flora. Finally, Spearman correlation analysis was combined to find the relationship between differential flora and differential metabolites in feces.

Results

(1) The results of Y-maze test and Elisa assay indicated that Sc-At could improve the cognitive dysfunction of AD model rats. (2) Metabolomics results showed that fecal metabolite levels were significantly different from those of rats in the blank group, and 18 potential biomarkers in feces were screened, mainly affecting linoleic acid metabolism, steroid hormone biosynthesis, sphingomyelin metabolism, riboflavin metabolism, etc. The 16S rDNA results showed that the abundance and diversity of intestinal flora in AD rats were destroyed, and the Sc-At treatment was able to reverse these changes. (3) Spearman’s correlation analysis showed a significant correlation between differential metabolites in feces and intestinal flora, further suggesting that Sc-At treats Alzheimer’s disease through the gut-brain axis.

Conclusions

In this study, we explored the mechanism of Sc-At in the treatment of Alzheimer’s disease by integrating fecal untargeted metabolomics and 16S rDNA gene sequencing, and the results showed that Sc-At exerts therapeutic effects on Alzheimer’s disease by improving the intestinal flora and related metabolic pathways.

Sulfur-doped biochar (S₄BC) was prepared with cherry kernel powder as carbon source, Na₂S₂O₃ as sulfur source and chemical activator. Na₂S₂O₃ can activate biochar through the reaction with carbon, intercalation of alkali metals and the generated gas rushing out of pores, and at the same time, active sulfur atoms are doped into biochar during pyrolysis. The physical and chemical properties of S₄BC adsorbent were evaluated by various characterization techniques. The results show that S₄BC calcined at 800 °C has huge specific surface area of 959.6 m²/g, developed pore structure, and high content of S (18.84 wt%). Moreover, due to the existence of sulfur and oxygen functional groups, S₄BC-800 provides sufficient active sites for the adsorption of Hg²⁺. According to Langmuir model, the maximum adsorption capacity of S₄BC-800 for Hg²⁺ is 724 mg/g at 313 K, and the adsorption speed is fast with excellent stability and reusability. The microfiltration membrane device based on S₄BC-800 can effectively remove the low concentration of Hg²⁺ in the solution. In this study, a simple method for preparing SBC materials is developed, which is not only of great significance as an adsorbent for Hg²⁺, but also provides a new choice for the preparation of heteroatom-doped materials.

The magnetic nitrogen-doped carbon nanotube is prepared by one-pot using waste plastics as feedstock in the existence of the urea and Fe(NO₃)₃ for Cr(Ⅵ) removal form wastewater. The characterization analysis indicates that the nitrogen is successfully doped on the magnetic nitrogen-doped carbon nanotube with specific surface area of the 158.71 m²/g and saturation magnetization of the 36.47 emu g⁻¹. The existence of the nitrogen group and Fe₃C contributes to Cr(Ⅵ) removal by complexation and reduction with adsorption capacity of the 27.47 mg g⁻¹. The adsorption data is fitting well with the Pseudo-second order model, demonstrating chemisorption of Cr(Ⅵ). The Cr(Ⅵ) removal mechanism analysis indicates that Fe⁰, Fe²⁺, H*, oxygen-containing group and nitrogen-containing group are crucial to Cr(Ⅵ) removal. The key mechanism of the enhanced Cr (VI) removal is the reductive capacity by dissolved Fe²⁺, which accounts for 23.6 % of the overall Cr(VI) removal. The magnetic nitrogen-doped carbon nanotube is prepared from waste plastic for Cr (VI) removal from wastewater.

For the first time, we used laccase (LA) and hydrogen peroxide (H₂O₂) in supercritical fluid of carbon dioxide (SCF-CO₂) to develop a method of bleaching cashmere fiber production in an ecofriendly way. The obtained results found that the whiteness of the cashmere was improved significantly involving a high bleaching efficient with this method, as well as influenced notably by the dosages of H₂O₂ and LA, bleaching temperature, pressure and duration. Various natural colorants on the cashmere sample were effectively decomposed and removed by the bleaching ingredients from the H₂O₂ and biologic catalyst of LA via an efficient transfer of those species onto cashmere surfaces from (H₂O₂ + LA+PEG1000 + H₂O)/SCF-CO₂ system. Particularly, this supercritical bleaching method with LA and H₂O₂ in SCF-CO₂ reduced the number of damages to the cashmere fibers. Furthermore, we also successfully validated the supercritical removal of colorants by using X-ray energy spectroscopy (EDS) and scanning electron microscopy (SEM) analysis. Strength measurements and thermogravimetric (TG) and differential thermogravimetric (DTG) analysis demonstrate that supercritical bleaching had a reduced impact on the thermal and mechanical properties of the cashmere fiber. An optimized enzymatic-oxygen bleaching process in SCF-CO₂ was further recommended by accompanying with a high whiteness value at 83.36 and an acceptable alkali solubility at 15.55 %. This developed supercritical bleaching method is prospective to be utilized for clear production of cashmere fibers by avoiding an extensive use of chemicals and the generation of heavy wastewater, as well as with less or non-effluent discharge.

Oxidative stress during sepsis could play a crucial role in the pathogenesis of several diseases, especially cardiovascular disorders. In fact, myocardial dysfunction during sepsis is caused by a number of chemicals, one of which is hydrogen peroxide (H₂O₂). Therefore, sepsis‐induced cardiomyopathy can be controlled through modulation of oxidative stress. Despite the encouraging pharmacological activities demonstrated by inorganic nanostructures, the mechanisms behind their blood protein interaction and antioxidant activity remain unclear. In order to advance the investigation for fabricating nanostructure platforms and studying their antioxidant effects as well as blood protein binding affinities, we explored the synthesis of manganese oxide (Mn₃O₄) nanorods via hydrothermal method and subsequent characterization using various techniques. The antioxidant effects against H₂O₂-induced oxidative stress in AC16 cardiomyocytes were then evaluated by different cellular and molecular assays. Additionally, the interaction of Mn₃O₄ nanorods with hemoglobin was investigated by experimental and and docking analyses. The results showed that synthesized Mn₃O₄ nanorods had an absorption peak in the range of 260 to 420 nm, vibration bands centered at 510 cm⁻¹, 629 cm⁻¹ and 410 cm⁻¹, 13 distinct XRD peaks, a rod-like morphology with a diameter range of 10 to 75 nm, a hydrodynamic size of 371.7 nm, and a zeta potential of −43.3 mV. Moreover, the antioxidant assays indicated that synthesized Mn₃O₄ nanorods can trigger a protective effect against H₂O₂-induced oxidative stress in AC16 cardiomyocytes through inhibition of reactive oxygen species (ROS) overproduction, increased content of superoxide dismutase (SOD) and catalase and glutathione (GSH), and reduction of caspase-3 activity. Furthermore, the fluorescence quenching mechanism of hemoglobin by Mn₃O₄ nanorods was determined to be controlled by a spontaneous and static quenching process, involvement of hydrogen bonds, a binding affinity (K_b) value of 10⁴ M⁻¹, and number of binding site (n) of around 1.03. Additionally, it was found that Mn₃O₄ nanorods induced a slight conformational change in the hemoglobin structure, where Tyr35 and Trp37 move to a hydrophilic microenvironment. In conclusion, it can be suggested that Mn₃O₄ nanorods with a reasonable plasma protein binding affinity can be used as an antioxidant co-therapy in cardiac dysfunction during sepsis.

As the main substate participating during the liquid metamorphism processes, the abnormal micro-environmental viscosity is closely associated with the occurrence and development of objective circumstance degradation. Thus, it is of great importance to establish the convenient detection method toward viscosity monitoring. This work is focused on extracting one kind of erucic acid-based molecular probe (EAd) for sensing viscosity fluctuations in liquids. The electron donor phenolic hydroxyl group and acceptor carboxyl have established in this molecular structure via a coincidental pathway. Twisted intramolecular charge transfer (TICT) was formed, and the rotatable conjugate structure was utilized as the recognition site. Due to the restriction of rotatable parts, higher emission fluorescent signal can be found in the high-viscosity micro-environment. And a large Stokes shift (83.3 nm in glycerol), narrower energy band, high selectivity (x = 0.56), adaptability, sensitivity, and good photo-stability, the applications of signal releasing in the complex liquid system can be achieved. Moreover, this natural probe EAd can identify the thickening efficiency in a non-invasively mode, in particular, viscosity fluctuations have been screened and spoiled samples can be distinguished by analyzing signal intensities. We hope that natural scaffold will provide a new reference toward liquid quality and safety inspection.

In the Haber-Bosch process (HBp), which uses elevated pressure and temperature to produce more concentration of nitrogen and hydrogen gases, 90% of the 175 million metric tons of NH₃ generated worldwide in 2016 were manufactured in this process. According to the road plan for sustainable ammonia production sustainably, using water as a reducing agent is the most effective way to fix nitrogen in close-quarters ambiance. A complete explanation of theoretical and practical work on electrocatalytic nitrogen reduction is provided in this article, with special attention paid to the low selectivity of nitrogen reduction to ammonia in comparison to protons to hydrogen. Since they are essential for accurately achieving high nitrogen production and Faradaic efficiency (FE), their information outlines electrocatalysts, electrolyte selection criteria, and managed experiment design. Under diverse conditions, the evolution of theory and experiment is examined. Finally, feedback is given on this field’s present issues and prospects.

Nanocomposite Zeolitic imidazolate framework (ZIF-8)@ Active Carbon (AC)–co-Chitosan (CS) was employed to fabricate polyether sulfone-based nanofiltration membranes. The ZIF-8@(AC-co-CS) nanocomposite was synthesized using a simple co-precipitation method and examined by field emission scanning electron microscope (FESEM) images, Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis, and X-ray diffraction pattern (XRD). Membrane properties used analyses such as FESEM, ATR-FTR, atomic force microscopy (AFM), porosity, water content, contact angle measurements, roughness assessment, pure water flux (PWF), separation efficiency evaluation, and fouling analysis. The surface roughness of the membrane with 0.01 wt% ZIF-8@(AC-co-CS) was nearly half that of the pristine membrane. Investigation outcomes revealed more excellent hydrophilicity for modified membranes. The water flux measured over three times greater for modified membranes than pristine ones. All modified membranes exhibited noteworthy rejection of sodium sulfate, achieving levels exceeding >93 %. The nanocomposite membrane was also assessed for removing two heavy metal ions, i.e., Cu and Cr. The results indicated a 55.0 % removal for Cu and 62.3 % removal for Cr by the virgin membrane, while that was >94 % and >97 % for the modified membrane, respectively. Also, higher separation efficiency was achieved for chromium ions compared to copper ions by the membranes. The nanocomposite membranes exhibited impressive dye rejection rates: >97 % for Methylene Blue, >95 % for Rhodamine B, >92 % for RB50, >94 % for RB21, >89 % for RY145, and >86 % for RY39. The FRR parameter significantly increased to >97 % for the modified samples. The nanofiltration performance of ZIF-8@AC-co-CS nanocomposite membranes exhibited a remarkable improvement compared to CS-based membranes.

Fibrin clots are crucial for hemostasis and the healing of wounds; nevertheless, excessive blood clotting plays an important role in many chronic diseases, including cardiovascular disease. In this study, we demonstrated the effect of the prepared AuNPs@PANI core/shell on the formed fibrin network. The synthesis of nanoparticles combining electrically conducting polymers polyaniline (PANI) and gold nanoparticles (AuNPs) is an appealing field of research currently because of their physical features and prospective applications in biochemistry. AuNPs showed surface plasmonic resonance (SPR) properties in the visible region at 520 nm then, after coating with PANI, there was a dramatic red shift to 610 nm. The morphological conformation was confirmed by characterization at the microscopic (TEM, SEM, EDX). The PANI shell plays a crucial role in this system, first enhances the stability of AuNPs core; also, the surface of the PANI shell has positive charges (zeta potential = +17.8 mV), leading to electrostatic interactions with fibrin clots that have negatively charged surfaces. The synthesized core/shell AuNPs@PANI showed good efficiency for degrading fibrin networks under 1:30 h of irradiation by an external source of laser light, which is a result of AuNPs’ ability to absorb light at 520 nm. The degradation of fibrin was observed using a scanning electron microscope (SEM), which showed a clear change in the shape of the network. The appearance of fibrous endings and gaping indicates the beginning of the degradation and melting of the fibrin network in different sites of the clot. Overall, this method could have a major influence on disease states, for example, deep vein thrombosis, through a localized, catheter-based approach.