Frontiers in Chemistry最新文献

The conversion of carbon dioxide (CO₂), a major greenhouse gas, into light olefins is crucial for mitigating environmental impacts and utilizing non-petroleum-based feedstocks. Thermo-catalytic CO₂ transformation into valuable chemicals offers a promising solution to this challenge. This study investigates the effect of potassium (K) and manganese (Mn) promoters on CO₂ conversion and C₂H₄ selectivity over CoFe-ZSM-5 zeolites. Structural characterization via FTIR, pyridine-FTIR, and PXRD confirmed the successful incorporation of K and Mn into CoFe-ZSM-5 at 80°C without significant structural changes to the zeolite framework. BET analysis revealed that metal incorporation did not substantially alter the surface area, while SEM and TEM analyses confirmed the preservation of ZSM-5 spherical morphology. Fixed-bed reactor experiments conducted at 350°C and 20 bar demonstrated that K and Mn synergistically enhanced CO₂ conversion efficiency and selectivity toward C₂H₄. The K-Mn/4Fe4Co-ZSM-5 catalyst (modified with 4% Co and 4% Fe) exhibited the highest performance, achieving 97% olefin selectivity. Furthermore, Mn and K promoters reduce the CO selectivity on the Co-Fe-ZSM-5 catalyst. These findings underscore the critical role of K and Mn in facilitating efficient CO₂ activation and directing the reaction pathway toward valuable olefin products.

CsPbBr₃ (CPB) perovskite has demonstrated unique advantages as a photoelectric material. However, its stability and optoelectronic properties exhibit significantly susceptibility to environmental conditions during practical applications. Additionally, the synthesis of CPB often involves complex procedures and stringent requirements for the experimental environment, resulting in low yield. In this study, we employed an aqueous-phase synthesis method to incorporate strontium into CPB, aiming to enhance the long-term stability of the perovskite in aqueous solutions. And the introduction of strontium (Sr) is expected to improve the photoluminescent properties of the perovskite. The results demonstrate that the synthesized perovskite remains stable in aqueous solution for up to 264 h, with enhanced photoluminescence intensity and a blue shift attributed to the incorporation of strontium. This approach significantly increases the potential value of CPB perovskite for applications in optoelectronic materials and devices.

Resistive type gas sensors based on wide-bandgap semiconductor oxides are remaining one of the principal players in environmental air monitoring. The rapid development of technology and the desire to miniaturize electronics require the creation of devices with minimal energy consumption. A promising solution may be the use of photoactivation, which can initiate/accelerate physico-chemical processes at the solid-gas interface and realize detection of flammable and explosive gases at close to room temperature. This work examines the mechanism underlying the increased sensitivity to various gases under photoactivation. The review is intended to clarify the current situation in the field of light-activated gas sensors and set the vector for their further development in order to integrate with the latest technological projects.

Introduction: Tuberculosis (TB), caused by the Mycobacterium tuberculosis (M.tb), remains a serious medical concern globally. Resistant M.tb strains are emerging, partly because M.tb can survive within alveolar macrophages, resulting in persistent infection. Protein kinase G (PknG) is a mycobacterial virulence factor that promotes the survival of M.tb in macrophages. Targeting PknG could offer an opportunity to suppress the resistant M.tb strains.

Methods: In the present study, multiple computational tools were adopted to screen a library of 460,000 molecules for potential inhibitors of PknG of M.tb.

Results and discussions: Seven Hits (1-7) were identified with binding affinities exceeding that of the reference compound (AX20017) towards the PknG catalytic domain. Next, the ADMETox studies were performed to identify the best hit with appropriate drug-like properties. The chromene glycoside (Hit 1) was identified as a potential PknG inhibitor with better pharmacokinetic and toxicity profiles rendering it a potential drug candidate. Furthermore, quantum computational analysis was conducted to assess the mechanical and electronic properties of Hit 1, providing guidance for further studies. Molecular dynamics simulations were also performed for Hit 1 against PknG, confirming the stability of its complex. In sum, the findings in the current study highlight Hit 1 as a lead with potential for development of drugs capable of treating resistant TB.

Oxidative stress is considered as the root-cause of different pathological conditions. Transition metals, because of their redox-active states, are capable of free radical generation contributing oxidative stress. Hemoglobin and myoglobin are two major heme proteins, involved in oxygen transport and oxygen storage, respectively. Heme prosthetic group of heme proteins is a good reservoir of iron, the most abundant transition metal in human body. Although iron is tightly bound in the heme pocket of these proteins, it is liberated under specific circumstances yielding free ferrous iron. This active iron can react with H₂O₂, a secondary metabolite, forming hydroxyl radical via Fenton reaction. Hydroxyl radical is the most harmful free radical among all the reactive oxygen species. It causes oxidative stress by damaging lipid membranes, proteins and nucleic acids, activating inflammatory pathways and altering membrane channels, resulting disease conditions. In this review, we have discussed how heme-irons of hemoglobin and myoglobin can promote oxidative stress under different pathophysiological conditions including metabolic syndrome, diabetes, cardiovascular, neurodegenerative and renal diseases. Understanding the association of heme proteins to oxidative stress may be important for knowing the complications as well as therapeutic management of different pathological conditions.

Introduction: Traditional methods for constructing synthetic nanobody libraries are labor-intensive and time-consuming. This study introduces a novel approach leveraging protein large language models (LLMs) to generate germline-specific nanobody sequences, enabling efficient library construction through statistical analysis.

Methods: We developed NanoAbLLaMA, a protein LLM based on LLaMA2, fine-tuned using low-rank adaptation (LoRA) on 120,000 curated nanobody sequences. The model generates sequences conditioned on germlines (IGHV3-301 and IGHV3S5301). Training involved dataset preparation from SAbDab and experimental data, alignment with IMGT germline references, and structural validation using ImmuneBuilder and Foldseek.

Results: NanoAbLLaMA achieved near-perfect germline generation accuracy (100% for IGHV3-301, 95.5% for IGHV3S5301). Structural evaluations demonstrated superior predicted Local Distance Difference Test (pLDDT) scores (90.32 ± 10.13) compared to IgLM (87.36 ± 11.17), with comparable TM-scores. Generated sequences exhibited fewer high-risk post-translational modification sites than IgLM. Statistical analysis of CDR regions confirmed diversity, particularly in CDR3, enabling the creation of synthetic libraries with high humanization (>99.9%) and low risk.

Discussion: This work establishes a paradigm shift in nanobody library construction by integrating LLMs, significantly reducing time and resource demands. While NanoAbLLaMA excels in germline-specific generation, limitations include restricted germline coverage and framework flexibility. Future efforts should expand germline diversity and incorporate druggability metrics for clinical relevance. The model's code, data, and resources are publicly available to facilitate broader adoption.

Oxidative stress-induced cardiomyocyte apoptosis was the primary causative factor of cardiovascular disease (CVD). However, the existing therapy drugs for oxidative stress were much less investigated, which underlined the necessity for new drug discovery and development. Herein, we aimed to synthesize several novel idebenone (IDE) derivatives and investigate the protective effect and mechanism of these derivatives against H₂O₂-induced oxidative stress injury in H9C2 cells by determining cell proliferation rate, detecting the reactive oxygen species (ROS) level, and the expression of related proteins. Additionally, the study also investigated the protective effect of IDE-1 pretreatment on Balb/c mice after hypoxia-reoxygenation. In vivo experiments, the damage to cardiomyocytes was assessed using hematoxylin-eosin (HE) staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. The results showed that IDE-1 possessed the highest antioxidant damage activity among all IDE derivatives, which could notably decrease the levels of intracellular ROS. Furthermore, the antioxidant mechanism was confirmed to be potentially linked to the expression levels of the oxidation-related pathway heme oxygenase-1 (HO-1) and the apoptosis-related pathway Bcl-2/Bax and caspase-3. Our results demonstrated that IDE derivatives could be a new research direction for the treatment of cardiovascular diseases associated with oxidative stress.

Safety of lithium-ion batteries (LIBs) has garnered significant attention. As an essential component of batteries, the separator plays a crucial role in separating the positive and negative electrodes, preventing short circuits, and allowing ion transport. Therefore, it is necessary to develop a high-performance separator that is both thermally stable and capable of rapid Li⁺ transport. Polyimide (PI) is a material with high thermal stability, but low electrolyte wettability and high interfacial resistance of PI restrict its application in high-performance LIBs batteries. MXene possesses excellent mechanical properties and good electrolyte affinity. PI/MXene nanofiber composite separator. Combines the high thermal stability of PI with the superior electrolyte wettability of MXene. It exhibits a high tensile strength of 19.6 MPa, low bulk resistance (2.5 Ω), and low interfacial resistance (174 Ω), as well as a low electrolyte contact angle of 29°, while retaining the high-temperature resistance and flame retardancy of PI. Batteries assembled with this composite separator demonstrated a specific capacity of 111.0 mAh g^-1 and a capacity retention rate of 66% at 2C. In long-term cycling tests of LiFePO₄ half-cells at 1C, after 200 charge-discharge cycles, the PI/MXene battery showed a discharge specific capacity of 126.7 mAh g^-1 and a capacity retention rate of 91%. Additionally, the battery operated normally at 120°C. The composite separator, by integrating the high thermal stability of PI with the excellent electrolyte wettability and conductivity of MXene, demonstrates significant advantages in enhancing battery safety and cycling performance. Through this composite structure can provide a more reliable and safe solution for high-performance LIBs.

[This corrects the article DOI: 10.3389/fchem.2024.1487084.].