Search Results (2,373)

The cooperation between microalgae and bacteria can enhance the carbon fixation efficiency of microalgae. In this study, a microalgae-bacteria coexistence system under high-concentration CO₂ stress was constructed, and the bacterial community structure of the entire system was analyzed using the 16S rDNA technique. Microbacterium sp., Bacillus sp., and Aeromonas sp. were screened and demonstrated to promote carbon fixation in Chlorella vulgaris HL 01 (C. vulgaris HL 01). Among them, the Aeromonas sp. + C. vulgaris HL 01 experimental group exhibited the most significant effect, with an increase of about 24% in the final biomass yield and a daily carbon fixation efficiency increase of about 245% (day 7) compared to the control group. Continuous cultivation of microalgae and bacterial symbiosis showed that bacteria could utilize the compounds secreted by microalgae for growth and could produce nutrients to maintain the vitality of microalgae. Detection of extracellular organic compounds of microorganisms in the culture broth by excitation-emission matrix spectral analysis revealed that bacteria utilized the aromatic proteinaceous compounds and others secreted by C. vulgaris HL 01 and produced new extracellular organic compounds required by C. vulgaris HL 01. The metabolic organic substances in the liquids of the experimental groups and the control group were analyzed by liquid chromatography-mass spectrometry, and it was found that 31 unique organic substances of C. vulgaris HL 01 were utilized by bacteria, and 136 new organic substances were produced. These differential compounds were mainly organic acids and their derivatives, benzene compounds, and organic heterocyclic compounds, etc. These results fully demonstrate that the carbon fixation ability and persistence of C. vulgaris HL 01 are improved through material exchange between microalgae and bacteria. This study establishes a method to screen carbon-fixing symbiotic bacteria and verifies that microalgae and bacteria can significantly improve the carbon fixation efficiency of microalgae for high-concentration CO₂ through material exchange, providing a foundation for further research of microalgae-bacterial carbon fixation. Full article

The application of metal–organic frameworks (MOFs) has attracted increasing attention in organic synthesis. The modification of MOFs can efficiently tailor the structure and improve the property for meeting ongoing demand in various applications, such as the alteration of gas adsorption and separation, catalytic activity, stability, and sustainability or reusability. In this study, carboxyethylsilanetriol (CEST) disodium salt was used as a dual-functional ligand for modified Al-MIL-53 to fabricate CEST-functionalized Al-MIL-53 samples through a hydrothermal reaction of aluminum nitrate, terephthalic acid, and CEST disodium salt by varying the molar ratio of CEST to terephthalic acid and keeping a constant molar ratio of Al³⁺/-COOH of 1:1. The structure, composition, morphology, pore feature, and stability were characterized by XRD, different spectroscopies, electron microscopy, N₂ physisorption, and thermogravimetric analysis. With increasing CEST content, CEST-Al-MIL-53 still preserves an Al-MIL-53-like structure, but the microstructure changed compared with pure Al-MIL-53 due to the integration of CEST. Such a CEST-Al-MIL-53 was used as the support to load Pd particles and afford a catalyst Pd/CEST-Al-MIL-53 for Suzuki–Miyaura C-C cross-coupling reaction of aryl halides and phenylboronic acid under basic conditions. The resulting Pd/CEST-Al-MIL-53 showed a high catalytic activity compared with Pd/Al-MIL-53, due to the nanofibrous structure of silicon species-integrated CEST-Al-MIL-53. The nanofiber microstructure undergoes a remarkable transformation into intricate 3D cross-networks during catalytic reaction, which enables the leachable Pd particles to orientally redeposit and inlay into these networks as the monodisperse spheres and thereby effectively preventing Pd particles from aggregation and leaching, therefore demonstrating a high catalytic performance, long-term stability, and enhanced reusability. Obviously, the integration of CEST into MOFs can effectively prevent the leaching of active Pd species and ensure the re-deposition during catalysis. Moreover, catalytic performance strongly depended on catalyst dosage, temperature, time, solvent, and the type of the substituted group on benzene ring. This work further extends the catalytic application of hybrid metal–organic frameworks. Full article

The benzene–toluene–xylene (BTX) system represents an energy-intensive petrochemical process with various industrial applications. Global climate changes have forced modern industry to act toward environmental safety, which requires technological changes. Thus, the divided wall column (DWC) represents a significant advancement in multicomponent mixture separation. To assess the impact of the conventional BTX process and its intensification proposal based on DWC technology, it is necessary to integrate an eco-efficiency approach that jointly analyzes the economic and environmental variables influencing the system, such as water consumption, CO₂ emissions, and utility costs. An auxiliary utility plant was also considered for more realistic results in terms of energy and water consumption, which was identified as a lack in many research studies that performed an overall sustainability analysis. The results showed that the DWC scheme is 37.5% more eco-efficient than the conventional counterpart, mainly due to a 15.6% and 30.3% savings on energy and water consumption, respectively, which provided a 15.5% and 16.7% reduction on CO₂ emissions and utility costs, respectively. In addition, all other environmental and safety indicators based on the waste algorithm reduction (WAR) were reduced by approximately 16%. Thus, the DWC proved to be a convenient technology with economic attractiveness and environmental friendliness. Full article

This article primarily develops a new technology for the rapid large-scale screening of isoliquiritigenin-transforming strains based on the MTHM (microplate reader–TLC–HPLC–UPLC-MS) method. ISO is a chalcone compound with potential pharmacological activity, and its rich substitution sites on the benzene ring provide a solid foundation for structural modification and drug development. This study screened approximately 1500 strains and employed a microplate reader, thin-layer chromatography, high-performance liquid chromatography, and mass spectrometry to verify the transformation products, identifying 15 strains with significant transformation capabilities. This study demonstrates that the optimized MTHM method is efficient and reliable, capable of rapidly detecting subtle structural changes in flavonoids before and after microbial transformation. During the transformation process, bioactive flavonoid compounds, such as amentoflavone and 5′-methoxyflavonoid, were discovered. Additionally, the experiments revealed that Czapek medium, modified Martin medium, and LB medium exhibited high efficiency in screening transforming strains. This research provides new technical approaches for ISO structural optimization and drug development while highlighting the important application potential of microbial transformation in natural product development. Future studies could further explore the metabolic potential of these strains, optimize transformation conditions, and promote the application of ISO in the medical field. Full article

Complete assignments of the ¹H and ¹³C NMR chemical shifts for the monoterpenes, borneol 1a and isoborneol 2a, as well as their derivatives (1b–1g and 2b–2g), in which the secondary hydroxy group is protected with various protecting groups, have been made in various solvents. Upon protection of the hydroxy groups in 1a and 2a, many protons and carbons within the bicyclic ring exhibited downfield or upfield shifts in their chemical shift values, facilitating the unambiguous assignments of these protons and carbons. These chemical shift values also showed excellent correlations with those obtained from density functional theory (DFT) calculations. Furthermore, the anisotropic effect of the benzene ring was estimated by the analysis of the iso-chemical shielding surface (ICSS) resulting from substituents introduced to the hydroxyl groups of 1a and 2a. Full article

Occupational exposure as a firefighter was recently classified as carcinogenic to humans by the IARC. Fire instructors’ exposure to carcinogenic PAHs is a major concern, and studies that have tried to assess the determinants of their exposure are scarce. An air and biomonitoring study was conducted in fire instructors performing simulated training exercises in enclosed containers. Air samples were collected, as well as urine samples from 22 firefighting instructors, and skin wipes were collected from FFs’ skin at the end of the exercises. PAH metabolites (1-hydroxypyrene, 3-hydroxybenzo(a)pyrene, 2/3-hydroxyfluorene, and 2/3-hydroxyphenanthrene) were measured in urine samples at three sampling times (beginning of shift, end of shift, and next morning). Airborne PAHs were dominated by low molecular weight compounds (naphthalene), and levels were as high as 67 µg·m⁻³ close to the containers, decreasing at higher distances. Skin contamination was observed both on the neck/face and hands/wrists of fire instructors and pilots. Ten times lower skin contamination was observed when nitrile undergloves were worn. High internal exposure was measured, with 1-hydroxypyrene and 3-hydroxybenzo(a)pyrene levels frequently exceeding maximum recommended values in occupational settings (up to 2.8 µmol/mol creatinine for 1-OHP, 14 µmol/mol creatinine for SOH-PAH, and 1.0 nmol/mol creatinine for 3-OHBaP), whereas benzene exposure was revealed to be very low. These types of exposure were found to derive both from dermal absorption (combustion products deposited on the skin) and inhalation (when removing SCBA outside the containers). Several recommendations are proposed in order to reduce both exposure routes (nitrile undergloves and half-masks in the vicinity of containers), harmonise decontamination (PPEs) and cleaning procedures, and prevent the dermal absorption of PAH from turnout gear. This study emphasises the complex PAH exposure profiles of fire instructors and characterises the main drivers of exposure, highlighting the need for better mitigation strategies. Full article

Benzene, a well-known carcinogenic airborne pollutant, poses significant health risks, particularly in industries such as petroleum, shoemaking, and painting. Despite strict regulations, chronic occupational exposure persists, contributing to the onset of acute myeloid leukemia (AML) and other malignancies. Benzene’s carcinogenicity stems from its metabolic activation, leading to increased oxidative stress, DNA damage, and cancer transformation. While its toxicity is well-documented, the link between genetic and epigenetic alterations and cancer susceptibility in exposed workers remains underexplored. This study aims to identify early biomarkers of benzene exposure and AML risk by analyzing gene expression and DNA methylation datasets from GEO DataSets, integrated with molecular pathway analyses, as well as miRNA-target and protein-protein network evaluations. This multi-approach led to the identification of nine deregulated genes (CRK, CXCR6, GSPT1, KPNA1, MECP2, MELTF, NFKB1, TBC1D7, ZNF331) in workers exposed to benzene, with NFKB1 showing strong discriminatory potential. Also, dose-dependent DNA methylation changes were observed in CXCR6 and MELTF, while selected miRNAs such as let-7d-5p, miR-126-3p, and miR-361-5p emerged as key post-transcriptional regulators. Furthermore, functional enrichment linked these genes to immune response, inflammation, cell proliferation, and apoptosis pathways. While network analyses highlighted NFKB1, CRK, and CXCR6 as central to benzene-associated leukemogenesis. Altogether, these findings provide novel insights into an early biomarker fingerprint for benzene exposure and AML susceptibility, supporting the future development of biomolecular-based targeted occupational health monitoring and personalized preventive strategies for at-risk workers. Full article

In this work, ceramic monolithic catalyst carriers based on zirconium dioxide (ZrO₂) were produced using fused filament fabrication (FFF). The active catalyst components were deposited on the resulting carriers using the wet impregnation method. The activity of the prepared monolithic catalysts was evaluated by catalytic oxidation of a mixture of aromatic volatile organic compounds: benzene, toluene, ethylbenzene, and o-xylene (BTEX). The efficiency of the prepared monolithic catalysts was investigated as a function of the geometry of the monolithic carrier (ZDP, Z, and M) and the chemical composition of the catalytically active component (MnFeO_x, MnCuO_x, and MnNiO_x) during the catalytic oxidation of BTEX compounds. The mechanical stability of the catalyst layer and the dimensional stability of the 3D-printed monolithic catalyst carriers were investigated prior to the kinetic measurements. In addition, thorough characterization of the commercial ZrO₂-based filament was carried out. The results of the efficiency of the prepared monolithic catalysts for the catalytic oxidation of BTEX showed that the 3D-printed model M, which contained MnFeO_x as the catalytically active component, was the most successful catalyst for the oxidation of BTEX compounds. The mentioned catalyst enables the catalytic oxidation of all components of the BTEX mixture (>99% efficiency) at a temperature of 177 °C. Full article

Quinazoline, a privileged scaffold in medicinal chemistry, offers promising potential in the synthesis of anti-Alzheimer’s disease (AD) drugs. This heterocyclic compound, characterized by its fused benzene and pyrimidine rings, enables the design of multifunctional agents targeting AD pathology. The drug-like aspects and pharmaceutical features of quinazoline derivatives have the potential to give rise to various therapeutic drugs. AD is a progressive neurodegenerative condition marked by memory decline, cognitive deterioration, and language disorders. Given its complexity and multifaceted nature, there is a pressing need to discover multi-target drugs to effectively address this debilitating disorder. A comprehensive literature review has demonstrated that quinazoline derivatives exhibit a wide range of therapeutic potential for AD. These compounds function as inhibitors of cholinesterases, β-amyloid aggregation, oxidative stress, and tau protein, among other protective effects. Here, we highlight the most significant and recent research on quinazoline-based anti-AD agents, aiming to support the development and discovery of novel treatments for AD. Full article

Polyvinyl butyral (PVB) is a specialty polymer primarily used as an interlayer in laminated glass applications with no current circularity plan after the end of its life. This study presents a comprehensive recycling strategy for postconsumed PVB wastes based on a remelting–restabilization approach. Thermo-oxidative degradation of PVB was analyzed under heat and shear stress conditions in an internal mixer apparatus. The degradation mechanism of plasticized PVB (p-PVB) and unplasticized PVB (u-PVB) was identified as chain scission through melt flow rate (MFR), intrinsic viscosity (IV), and yellowness index (YI) characterization. Six different antioxidant (AO) formulations were screened for their effectiveness in inhibiting degradation in both neat u-PVB and p-PVB, as well as retrieved PVB. The phenolic antioxidants 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol were found to be the most effective ones based on MFR, oxidation onset temperature (OOT), and YI evaluations, while the optimal AO concentration was determined at 0.3% w/w. Furthermore, upscaling of the process was achieved by mixing virgin PVB and high-quality retrieved PVB wastes with AOs in a twin-screw extruder. Testing of the recycled samples confirmed that the selected AOs offered resilience against degradation at reprocessing and protection during the next service life of the material. Full article

Developing efficient strategies for VOC emission abatement is an urgent task for protection of the environment and human health. Complete catalytic oxidation exhibits advantages, making it an effective, environmentally friendly, and economically profitable approach for VOC elimination. Pd-based catalysts are known as highly active for hydrocarbon catalytic oxidation. The nature of carrier materials is of particular importance because it may affect activity by changing physicochemical properties of the palladium species. In this work, Al₂O₃, CeO₂, CeO₂-Al₂O₃, and Y-doped CeO₂-Al₂O₃ were used as carriers of palladium catalysts. Methane and benzene were selected as representatives of two types of hydrocarbons. A decisive step in complete methane oxidation is the first C–H bond breaking, while the extraordinary stability of the six-membered ring structure is a challenge in benzene oxidation. The support effect was explored by textural measurements using XRF, XRD, XPS, EPR, and TPR techniques. Three ceria-containing samples showed superior CH₄ oxidation performance, achieving 90% methane conversion at about 300 °C and complete oxidation at 320 °C. Evidence for presence of Pd²⁺ species in all samples regarded as most active was provided by XP-derived analysis. Pd/Y-Ce/Al catalysts exhibited very high activity in benzene oxidation by reaching 100% conversion at 180 °C. The contributions of higher Pd and Ce³⁺ surface concentrations, the presence of O₂⁻-adsorbed superoxo species, and Pd⁰ ↔ PdO redox transfer were considered. The potential of a simple, environmentally friendly, and less energy demanding mechanochemical preparation procedure of mixed oxides was demonstrated. Full article

Wuyi Rock tea (WRT), originating from the northern region of Fujian province, has a good reputation for its distinctive Yan flavor and floral–fruity aroma. The aroma quality, an essential element of the Yan flavor, undergoes various changes during the manufacturing process of WRT. To enhance the understanding of the formation patterns of WRT aroma and its influence on the flavor quality of WRT, we utilized both manufactured WRT (Rougui tea) and primary tea as materials. Utilizing a sensory evaluation, detection of volatile compounds, and multivariate statistical analysis, we identified and characterized the distinctive volatile components present in WRT. The sensory evaluation and radar chart analysis revealed that the primary tea exhibited a strong and lasting aroma, along with a mellow taste and a prominent Yan flavor. Through gas chromatography time-of-flight mass spectrometry (GC-TOF MS), a total of 251 volatile compounds were identified. The odor activity value (OAV) was calculated to identify key aroma-active compounds in the primary tea. The results indicated that a total of 14 compounds had an OAV greater than 1.0, including (2-nitroethyl) benzene, indole, and geranylacetone. These compounds exhibited floral and fruity aroma attributes. They primarily formed and accumulated during the latter stages of WRT. Using a partial least squares discrimination analysis (PLS-DA) combined with a variable importance in projection (VIP) score greater than 1.0 as a criterion, a total of 89 compounds were identified. Furthermore, out of the selected compounds, 15 types, including geraniol, 1-nonanol, and 1-butyl-2-ethyl-cyclopropene, were found to exclusively exist during the enzymatic manufacturing stages, particularly during the intermediate and later phases of the turn-over process (the last-three-times turn-over treatments), exhibiting predominantly floral and sweet fragrances. In contrast, during the non-enzymatic stages, only four compounds, such as pentanoic acid and phenylmethyl ester, were detected, exhibiting a fruity aroma profile. These volatile compounds significantly influenced the quality attributes of the final tea product, resulting in strong and lasting characteristics, particularly marked by a pronounced floral and fruity aroma. This study revealed how the aroma quality in WRT is developed and pinpointed possible volatile compounds that react to post-harvest treatments, thereby offering valuable insights relating to the intelligent production strategies of WRT. Full article

The development of highly efficacious materials for the removal of toxic heavy metal-based oxo-anions is of utmost importance. Herein, an ionic porous organic polymer (designated as HB-IPOP) was synthesized through a quaternization reaction between hexa(imidazole-1-yl)benzene and 5,5′-Bis(bromomethyl)-2,2′-bipyridine. HB-IPOP exhibited high saturation uptake capacities, specifically 292 mg·g⁻¹ for Cr₂O₇²⁻ and 531 mg·g⁻¹ for ReO₄⁻, and demonstrated exceptional selectivity for both Cr₂O₇²⁻ and ReO₄⁻. Additionally, HB-IPOP demonstrates high recyclability, allowing its reuse over at least five cycles. DFT calculations confirmed that the superior interaction sites and binding energies of HB-IPOP with Cr₂O₇²⁻ and ReO₄⁻ outperform the affinities of other competing anions. This theoretical validation aligns with the experimentally observed high capacity and selectivity of HB-IPOP for these oxo-anions. Hence, HB-IPOP emerges as a promising candidate to replace current adsorbent materials in the effective removal of Cr₂O₇²⁻ and TcO₄⁻ anions from water. Full article

The effects of photochemical reactions induced by UV radiation in solutions of metal phthalocyanines were carried out to determine the factors that might influence the photostability of photosensitized phthalocyanines. Three different indium phthalocyanines, including the diindium triple-decker phthalocyanine, In₂Pc₃ (1), sandwich indium phthalocyanine, InPc₂ (2) and iodoindium phthalocyanine, InPcI (3) in benzene, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), dichloromethane (DCM) and 1-chloronaphtalene, were studied. The rate of decay of absorption is explained by a decomposition reaction that is of first-order kinetics with respect to the phthalocyanine concentration. In general, the presence of ligand I⁻ in phthalocyanine InPcI enhances the rate of decomposition. The kinetics of the degradation process proved to depend on the molecular structure of the complex and seems to be controlled by interactions of the macrocycle bridging nitrogen atoms with the solvent molecules. The indium phthalocyanines in benzene displayed the capacity for singlet oxygen generation. Full article

Inflammatory bowel disease (IBD) is characterized by uncontrolled, chronic relapsing inflammation in the gastrointestinal tract and has become a global healthcare problem. Here, we aimed to illustrate the anti-inflammatory activity and the underlying mechanism of methyl 3-bromo-4,5-dihydroxybenzoate (MBD), a compound derived from marine organisms, especially in IBD, using a zebrafish model. The results indicated that MBD could inhibit the inflammatory responses induced by CuSO₄, tail amputation and LPS in zebrafish. Furthermore, MBD notably inhibited the intestinal migration of immune cells, enhanced the integrity of the gut mucosal barrier and improved intestinal peristalsis function in a zebrafish IBD model induced by trinitro-benzene-sulfonic acid (TNBS). In addition, MBD could inhibit ROS elevation induced by TNBS. Network pharmacology analysis, molecular docking, transcriptomics sequencing and RT-PCR were conducted to investigate the potential mechanism. The results showed that MBD could regulate the TLR/NF-κB pathways by inhibiting the mRNA expression of TNF-α, NF-κB, IL-1, IL-1β, IL6, AP1, IFNγ, IKKβ, MyD88, STAT3, TRAF1, TRAF6, NLRP3, NOD2, TLR3 and TLR4, and promoting the mRNA expression of IL4, IκBα and Bcl-2. In conclusion, these findings indicate that MBD could be a potential candidate for the treatment of IBD. Full article